We walked all five miles to town. I don't know whether or not Elsa had a car, but really I didn't mind. It gave me time to talk with her. Or rather her talk to me. This Elsa, this version of her from the past, was a real talker. She loved to say whatever was on her mind: dreams for the future, school plans, how the farm was going, the sights to see in town, anything at all. It was such a sharp contrast to the future Elsa who was all business that I almost wondered if I was with her twin.

Her favorite topic by far was her degree and how she was going to change the world. "There are so many hereditary diseases out there, and who's talking about them? Hardly anyone. But I can fix them. I know I can."

I couldn't help smiling. It would probably blow her mind if I told her that in the future she made a whole human.

Town was small. There were a couple of beat up buildings that had been splattered with new paint to make them more appealing. Elsa knew exactly what she wanted, popping in and out of stores with armfuls of things which she gave me. Seeds, mostly. A bag of something that smelled disturbingly like fertilizer. Pliers, a shovel, rope.

"Don't you have this stuff back home?" I asked as she added a bucket to my aching arms. She shrugged.

"I do, but it's not for me."

"Who is it for?"

She bloomed a brilliant red. "If I tell you, you can't tell my dad."

Now I really was curious. Why wouldn't she be able to tell her dad about this stuff? But I nodded to show I wouldn't tell. She shuffled her feet.

"There's a homeless shelter. In town. They don't ever get donations, and they're really struggling. Especially now that the hospitals are eating all of our tax money. And there's a farm down the road that got foreclosed and I figured . . . this is all for the homeless shelter. And the farm too, when I finally save enough."

I blinked a couple of times. "Why can't your dad know that?"

"He . . . he doesn't want me wasting my 'hard earned money.'"

Sure Elsa and her father lived on a farm, but they hadn't struck me as poor. She had told me her dad used to be a doctor. And she was getting a genetics degree, only helping at the farm part time. And if Elsa was talking about buying a whole farm, she must have a lot of money set aside. I couldn't understand why this was such a big deal. Elsa glanced at me and shrugged.

"We don't agree all the time," she said. "That's all. Let's go back to the farm. I need to get these somewhere safe, and I want to show you something else."

When she said that her eyes sparkled mischievously. She walked away before I could protest, humming a soft tune to herself. I shook my head and moved to follow her, but my eyes caught on a nearby building. The only one bursting with life, or death. A hospital.

Time was running out.

———

After Elsa had hidden the supplies in her barn — "the best place is in plain sight" — she pulled out a ladder and leaned it against the side of the barn. I watched, heart pounding, as she started the ascent to the barn roof.

"Are you sure that's a good idea?" I called. "The roof doesn't look really . . . safe."

"You sound like my dad!" she called back with a grin. "Come on, scaredy pants. I've been up here hundreds of times."

I couldn't share what I was actually afraid of: seeing me on the roof with Elsa wouldn't exactly endear me to her father. He might want to stab me with a pitchfork. Or two. Or three.

But then I remembered that sitting on the barn roof was one of Elsa's favorite memories. I scrambled up the ladder after her.

Shingles creaked as I eased myself across the grainy surface. Elsa was already waiting. I sat beside her as the sky was stained orange and pink. If the sun was already setting, we had spent more time in town than I had realized. I could see her home, the field of dandelions, and the cornfield. It reminded me unnervingly of Elsa's favorite memory she had shown me back in the memory chamber.

"What do you know about time travel?" I blurted out. She laughed.

"I'm getting a degree in genetics, not fiction."

"But, for example, if you went back in time and changed something, would it change other things too in this big domino effect? Even the little things?"

She stared thoughtfully at the dandelions for a moment. Her fingers played with her braid, flipping it back and forth. "Little things would always change, but I bet that time would try to fix itself. Some things, even when you try and stop them from happening, will just happen another way."

I really didn't like what she was implying. I had only wanted to know if me coming to the past would have gotten rid of her favorite memory, and now she was talking about it being impossible for me to keep her from catching Bone Fever. She couldn't be right. Both Elsas couldn't be right. I could save her and the world. I could. I just had to try harder.

"Why the time travel questions? Are you writing a book or something?"

"Just curious," I replied, trying to calm my racing pulse. This past Elsa hadn't studied time travel, not yet at least. She couldn't be right.

"What would you do if you could travel in time?"

Ouch. But an easy answer. "I would save the people I care about."

"And I would save everybody." No surprise there. "But can I share a secret with you?"

"Sure."

"I don't think my dad would save anyone. I think being a doctor changed something. He doesn't trust other people anymore."

I didn't reply. I didn't have a response in the first place. But I was here, protecting her, gathering information, and trying to think up a plan. That was enough.