"You want us to do what now?" Max asked.

"Go back in time and give me a door," Dr. Octavius said. "This door to be precise." He pointed at a door sitting on the table. "You're also going to need these other two doors here."

"I'm afraid we don't understand," Zeke said.

"Yes, it's all a bit complicated. Let me begin with door number three. This door should look familiar to both of you as you've both gone through it before."

"We have?"

"Yes. This is the exact same door that currently sits at the bottom of a pond in the Buttermoss Gardens and leads back to Earth precisely at Dr. Wentworth's septic tank."

"Wait a minute, how can that be the door that leads back to Earth when, as you say, it's currently sitting at the bottom of a pond?"

"I assure you it is the same door. Lothar just built it and programmed it with the coordinates I gave him. And the reason it's at the bottom of a pond is because the two of you went back in time and put it there. I even wrote a little note about it on the inside of the door just now. The same note that's always been inscribed there, but which I never understood until this very moment."

"So how did we go back in time and put the door there?" Zeke asked.

"Ah, yes," Dr. Octavius said. "That's where door number two comes in. Perhaps I should let Lothar explain as he's the one who built it."

"Yes, indeed I did," Lothar said. "I've been experimenting with different kinds of doors for a while now. Most doors lead to other universes as you well know. But this door is special because it only works in this universe. It's a time travel door. Now I've only been able to perform limited experiments on it, but I'm confident it will serve our purposes. And at the moment, time is of the essence."

"Yes," Dr. Octavius said. "Vance is most likely on his way here as we speak with the express purpose of destroying this lab and everything in it, which would be very, very bad. This leads us back to door number one. This is the door I need you to give me in the past. For you see, this is the very door that I first went through to come to Quartzwater City. For that matter, this is the door that you first went through as well, Zeke."

"The floating door in your lab? That's it?"

"This is it. Believe me, I spent a very long time studying that door. I know it better than I know the back of my hand. This is indeed the door. I never knew how I came to be in possession of it, but now I know I sent you back in time to give it to me. It's very important that Vance not destroy this door before it goes back in time and comes into my possession, because if he does there is no possible way that I would have ever come here and everything that has happened since will become undone and a paradox of that magnitude is likely to rip a hole in the fabric of reality and might possibly destroy all of existence as we know it. Are you grasping the significance of this?"

"I think so," Zeke said.

"Okay, it sounds simple enough," Max said. "Use the time travel door to go back in time and give you that door. Got it, Doc."

"I'm afraid it's not very simple at all," Dr. Octavius said. "Things always get complicated when time travel is involved. Speaking of which, please pay attention because this is of the utmost importance. The first rule of time travel is that whatever happens always happened."

"You mean you can't change the past?" Zeke asked.

"Well, yes and no. As you may recall I've told you before about the theory of infinite universes."

"Yeah I remember that," Max said. "That was when you told me that any universe I can possibly imagine exists somewhere. I still haven't been able to find my dream universe yet."

"Well, it's unlikely you'd stumble on it randomly. Infinity is a very large number. In fact, it's beyond numbers as we understand them. It also encompasses a little more than just imagining universes. Some universes are astonishingly different from our own, whereas a vast amount are extremely similar. In fact, it is believed that every decision you make spins out a different universe. If you come to a fork in the road and you choose to go left, there also exists a different universe where everything is exactly the same except you chose to go right. If you go to a restaurant and order a skunk burger, there's also another universe where you ordered a firefly salad instead. Do you follow?"

"Yes," Zeke said. "Every choice we make creates new universes."

"Yes," Dr. Octavius said. "Now most of the time this has very little effect on us. We have no way of accessing those other universes and the versions of ourselves in those universes have no way of accessing us. We just diverge and continue on our separate paths none the wiser and without any noticeable effect on us at all. However, when you get time travel involved things become much more dicey. Have you ever heard of the grandfather paradox?"

"Is that the one where you go back in time and kill your own grandfather as a young man, thus ensuring that you'll never be born, which in turn means you couldn't have gone back in time in the first place to kill your grandfather?" Zeke asked.

"Yes," Dr. Octavius said. "Imagine such a scenario, if you will. It's a relatively

small paradox. It's possible something like that could do damage to reality or you might think that you would simply vanish from existence. But I believe something else would happen. You kill your own grandfather as a young man, an event that never happened in your own universe, and in effect you've found yourself in a new parallel universe that diverges from the one you previously inhabited. You would continue to exist, because there still exists the universe you were born in, in which you did not travel back in time and murder your grandfather. But now you're no longer in that universe. You've created a new universe by making a choice, a universe that no version of you will ever be born into but which you now inhabit. Are you following along so far?"

"It's kind of confusing, but I think I've got it," Zeke said. "Time travel can also be travel to a parallel universe if you do something that didn't happen in the past of your own universe."

"Yes, this is why it's important that you don't alter any major historical events if

you wish to remain in your own universe. Everything that happened must happen the same way. Don't prevent the assassination of Abraham Lincoln. For that matter, don't kill Hitler. And for the love of God, don't kill your own grandfather. There's no way to alter the past of your own universe. That's set permanently in stone. All you can accomplish by doing any of those things is spin off parallel universes. And that doesn't do us any good because it's very important that this door gets to me in my own timeline. Besides, remember what Lothar told you about the time travel door?"

"That it hasn't been tested very extensively, thus meaning all the bugs might not be worked out and it could be incredibly dangerous?" Zeke asked.

"Although that is true, that's not what Dr. Octavius is referring to. The important thing to remember here is that the time travel door works in this universe and this universe only. In any other universe it is merely a door. So if you travel back in time and alter history in any way, thus creating a new universe, you will be permanently stranded in that universe because the time travel door will not function."

"It kind of seems like that's one of the bugs that could maybe stand to be worked out."

"There's no time for that, which is ironic because in theory we have all the time in the world with a time travel door at our disposal. But door number one needs to go back to Dr. Octavius before Vance gets here. I can't risk using the time travel door to travel elsewhere in time and work out all the bugs. If I do something wrong, I may create a new universe where it no longer works and thus become stranded, meaning Vance will destroy Dr. Octavius's original door to Quartzwater City, which as previously mentioned will probably not just spin off a parallel universe. It's more likely to do extensive damage to reality."

"Okay, okay, we get it. We've got to use the door as is."

"I wouldn't fret about the door too much," Dr. Octavius. "The fact that we're here having this conversation gives me confidence that you will be successful in your mission. Remember whatever happens always happened. That means that you always went back in time and gave me the door. And whatever you do in the past you always did. That's how I got here in the first place."

"Of course something could always go wrong with the time travel door after they give you door number one," Lothar said thoughtfully. "All we know for sure is that you received the door. If they do something stupid after the fact, they could still be stranded forever in some other universe."

"That's true," Dr. Octavius said. "Try not to do anything foolish after you give me the door."

"Okay," Max said. "So we travel back in time and just knock on your door and say, hey Doc, here's a door?"

"Oh, heavens no," Dr. Octavius said. "Things must occur in precisely the manner they always occurred in order for you not to create parallel universes. So let's run through this step by step and make sure you understand exactly what must occur. The door comes into my possession back on Earth in the past. Earth exists in a different universe, so the time travel door will not work there. So you're going to have to travel back in time here in this universe. It's not important to know the exact date, although there is a fairly specific range. You have to travel far enough back to a point before I ever came here. But you can't go too far back or you won't be able to get the door to me. And if you get super crazy and travel into the long distant past, you might get stomped on or eaten by whatever sort of prehistoric creatures inhabited this universe. No, what you need to do is travel back just far enough to a point in which you can be sure that precedes the first time I ever came here."

"How are we supposed to do that?" Max asked.

"Ask around. See if anyone knows who I am. I made a name for myself pretty quickly. You can also check if my lab exists, but be careful not to interact with me before I met you, unless you put on a disguise or something. Because I don't remember meeting you before I met you. Unless, of course, I talked to you in the past and didn't know it was you. Regardless, once you've determined that is the case, you must take door number three to the pond in the Buttermoss Gardens. This is the door that leads to Earth. Drop it in the pond and leave it there. After all, that's how it got there in the first place. Use that door to travel to Earth. The timeline of Earth and Quartzwater City are closely related so you should cross over to Earth's past. At this point the time travel door will no longer function, but if you do everything correctly that shouldn't be a cause for concern."

"It sounds kind of concerning," Zeke said.

"Yes, but you forget you'll be carrying a doorway to Quartzwater City. One that I believe you left on the doorway to my lab. And you should travel automatically to the date that you left it for me because I found it on the day that you traveled to. Do you understand?"

"I think so. So we just drop the door outside your lab and then go through it back to Quartzwater City?"

"Unfortunately, it isn't that simple. Unlike most of the doors you may be familiar with, this one doesn't operate under its own power. It has to be hooked up to the proper electrical configuration. You'll have to wait for me to do that in the past before you'll be able to travel back through it."

"Uh oh, how long of a wait are we talking about here, Doc?" Max asked.

"Not long. Perhaps twelve to eighteen hours, depending on how long it was between when you dropped off the door and when I found it. Allow me to walk you through the timeline of what happened that night and the next day. It's important that you understand this if you wish to make it back here, which I believe you did based on the events of the timeline. I was working late in my lab that night, attempting to build a laser powered mousetrap. I wasn't having much success and I was generating a ton of garbage in the process. I yelled for my lab assistant at the time to take the garbage out but he had already left for the night without sweeping or emptying the bins, which is partly why the garbage was piling up so much. That was the young man before Maurice. Can't recall his name at the moment. Nice boy, but a terrible lab assistant. Not sure why I didn't fire him."

"Um, that was me, sir," Zeke said.

"Oh yes, I recall now. Yes. You were a terrible lab assistant. It wasn't unusual at all for you to leave without finishing your cleanup duties. At any rate, I was running out of space to work and you had abandoned your post, so I had no choice but to run the garbage out myself. As I took it outside I noticed a door leaning up against the wall of my lab. At first I thought someone was attempting to use my garbage bins to dispose of an old broken door, but as I studied it I realized it was in perfectly fine condition. So I grabbed it and brought it inside. I didn't have a good place to put it, so I brought it into my secret back room. As I did that I began singing a delightful cat food jingle to myself, whereupon the door froze into the air and refused to budge, which was quite mystifying to me at the time, but which I now know Lothar programmed it to do exactly that. It's a password protected site specific door. So I opened it up, but it didn't lead anywhere yet. That's because it wasn't hooked up to the electricity, which I now know is a requirement I also instructed Lothar to build into the door. Once the electricity was hooked up it created a permanent stamp of the door, which from that point on will allow any door to become a perfect replication of that door, provided a person knows the proper password and location to place it. This was an important component to add because, as you may recall, some idiot destroyed the original door."

"Now that wasn't my fault," Zeke said. "Trevor Mastodon was trying to come through and kill all of us. I managed to stop him and save the day. The door was just collateral damage."

"Yes, yes. The important thing is I could use any old door to replace it, which is in fact what I did. This means we won't have to go through any more time travel shenanigans in the future to get the proper door to me a second time. And if the current door ever breaks it can be easily replaced. It also means we won't have to burden you with a fourth door now, because the door I acquired in the past to create the new door will already be at the store I bought it from."

"Speaking of which, I've designed all three doors to fold down small enough to fit into your pockets," Lothar said. "Just remember to unfold them when you need to use them and leave doors number one and three unfolded when they get to their proper locations so Dr. Octavius can find them. The time travel door will automatically fold into your pocket after each use, so as not to attract extra attention wherever you end up. Just unfold it when you need to use it again."

"So anyway, I didn't hook the door up to electricity that first night because I didn't know it needed to be connected to electricity. I didn't even know what the door did. I just knew it was stuck in the air. The strangeness of this deterred me from my mousetrap project for the night. I tried to return to it, but my heart wasn't into it anymore. So I ended up going home and flipping on the television. That's where I saw some delightful little cartoon called "Schoolyard Jams" or something of the sort. The important thing here is that it contained a very catchy song about electricity. Catchy enough that it was still stuck in my head when I awoke the next morning and returned to my lab. And then something clicked. It occurred to me to try connecting the strange door that I had found to an electrical current, which I did immediately. But before I had a chance to try it out, I received a phone call from the Mad Scientist's Depot informing me that some bunsen burners I had ordered had finally arrived. I had been waiting for them for quite some time, so I immediately ran down there to pick them up. When I returned to my lab I found the electricity to the door was still turned on. I could have sworn I turned it off before I left, but I have been known to be absent-minded at times."

"You?" Zeke said. "Absent-minded? Nah, I don't believe that."

"At any rate I think I did turn the electricity off. I believe my trip to the Mad Scientist's Depot provided the two of you with your opportunity to travel back through the door and return to Quartzwater City. I took my first trip there myself after I returned and found the electricity on. After exploring for a while I eventually discovered the door you left in the pond at Buttermoss Gardens and travelled back home. And the rest, as they say, is history."

"So you're saying that we successfully delivered the door to you and traveled back through it because what happened in the past always happened?"

"Yes. Now remember you will only have a limited window to go back through the door, as my trip to the Mad Scientist's Depot only took about half an hour. Once you return to Quartzwater City, the time travel door should begin functioning again, provided you haven't altered anything in the past and thus created a parallel universe. At that point you can use the time travel door to return to here and now."

"Okay, so how exactly does this time travel door work?"

"As I said, it is still in a highly experimental stage," Lothar said. "So I can't give you precise instructions. You're going to have to use a little bit of trial and error. But there's a small dial on the front of it. Turning it left will send you back in time, turning it to the right will send you forward. Now, you may notice there's a prominent zero here. This marks the time and place that you left from. Turning the dial to zero should in theory lead to the exact moment and location that you departed from, although in actual practice there may be some small variance. The farther you travel in time, the more variance there may be in your location. You'll still be in this universe, but you might pop out five blocks away. This is one of the small bugs I haven't worked out yet. But in the timeframe we're talking about it should only dislocate you somewhere within a ten mile radius, which for all intents and purposes shouldn't affect you too much."

"And again, remember, once you're in the past don't alter anything that you know for sure happened. If you don't know whether or not it happened, you're most likely okay. If you accidentally step on an ant or swat a fly, you probably won't create a parallel universe, because you will always have done so. Now, this is very important. Do either of you ever recall talking to yourselves in the past or interacting with yourselves in any manner whatsoever?"

"Not that I can recall," Zeke said.

"I mean, I talk to myself all the time," Max said. "But I'm assuming you mean another version of me, in which case, no."

"That means that you never did interact with your past selves and thus must not do so. If you happen to catch sight of yourself in the past you must avoid all contact. Now if you happened to remember meeting yourself in the past it would be okay, but since you don't, you must not. Are you still clear on this?"

"Yes. Whatever happened always happened."

"All right, well, if there's no further questions, why don't you head back in time now. After all, there's no time like the present."

"To start you off I'm just going to turn the dial to the left a tiny little bit," Lothar said. "You probably won't go back far enough, but you definitely won't overshoot your mark. Like I said it's going to be a bit of trial and error, but I would err on the side of small turns of the dial, not big ones."

"All right, well let's stop jibber-jabbering and try this puppy out," Max said as he stepped through the time travel door.

"Well, this should be interesting," Zeke said. "Here's hoping we don't strand ourselves in another universe." He let out a little gulp and followed Max through the door.

Suddenly there was a thumping sound from a nearby cabinet.

"Finally! I thought we'd never leave!"