Castiel hovered near the doorway, trying not to seem anxious and failing.

"C'mon in, son. The cars ain't gonna fix themselves out there."

The teacher beckoned him into the classroom with a nod of his trucker cap. He was dressed in coveralls, and he wiped his grease-covered hands on his thighs before heading over to his desk. Castiel found a stool around a workbench where the rest of the class was sitting.

When Dean walked in with Alastair, Tom, and Brady, Castiel wasn't surprised. He tried to shrink a little behind Meg Masters, hoping her blonde bob of a haircut would shield him from being noticed.

"My name's Mr. Singer. Welcome to Auto Shop, part two to the school district's stupid idea to force you kids to take a class most of you are gonna hate. But since I ain't the one makin' the rules, I'm gonna make this as painless as possible as long as you follow my instructions and don't act like idjits while you're here. Got that?"

"Are we going to have to, like, get dirty and stuff?" asked a girl Castiel didn't know.

"If you, like, wanna pass this course, then yeah," Mr. Singer answered with a scoff. "You'll learn how to change a tire, fix a flat, check your fluids, and other basics of car maintenance. We won't be doin' any heavy-duty auto repair work in this class, though."

"Thank God."

"Yeah, we all have a lot to be thankful for," Mr. Singer mumbled. "All right, let's take attendance."

The class broke out into quiet conversation while Mr. Singer readied his attendance book.

"Okay, uh, Ag...uh, Ag...nu..."

"It's actually pronounced 'Ahn-yoos,' Mr. Singer," Castiel offered helpfully. "My last name, 'Agnus,' is Latin you see, and — "

"Great, kid. Good to know. Your first name's Castiel? Did I get that right?"

Alastair cleared his throat loudly, and then fake-coughed a softer "Fag!" under his breath.

Sniggers erupted around him and he shrunk down behind Meg again.

Mr. Singer didn't hear the insult tossed at Castiel, but even if he had, chances were he would be like Coach Zazel and other teachers and simply ignore it. Ms. Milton might have stuck up for him, if she witnessed something blatant. Alastair, however, had developed a subtle way of terrorizing him every day and had never been reprimanded. Castiel couldn't tell anyone, either, because that would only cause more problems.

He'd thought about standing up for himself, imagining a moment in which he lashed out and lost control. He had dreams about it — feeling the satisfying crunch when his fist met Alastair's nose, or slamming Alastair's face into the lockers, or a dozen other terrible things. Even if Castiel did try and fight back, it would be short-lived. Alastair was taller than him and had the muscled body of an athlete. Castiel wasn't afraid, exactly, but he was cautious and aware of his limits. Taking on Alastair, he knew, was one of them.

"Did y'hear me, son? I asked if I got the 'Castiel' part right."

"You did, Mr. Singer," Castiel responded, barely audible.

"Fine. Everyone answer when I call out your first name."

There were a few more giggles and some talking as Mr. Singer made his way around the room. Alastair, Tom, and Brady were deep in conversation with Dean, and Castiel noticed him glance his way a few times. He tried to ignore them and pulled Hamlet from his bag until Mr. Singer called them all to attention.

"Today we're gonna go over one of the most important basics: tires. Okay? Let's get started."

The students moved in a group to the wide garage bay that held an ancient Chevelle. Mr. Singer bent down next to the driver's side front tire, and patted its side.

"This part's the sidewall. Up here, where all the grooves are, is the tread. It's cut in a pattern to provide traction on the road. We're gonna check to see if we need new tires first. What I wanna do is turn the steering wheel and look over the whole tire. Turn to the right and left as far as she'll go, and get a good look across the surface of the tire. Got that? Anybody got any ideas what to look for?"

Dean was the first one to raise his hand.

"What's your name again, son?"

"Dean. Dean Winchester."

"All right Dean, what's one of the most common ways to know if your tires are wearin'?"

"You should look for cracks in the rubber, bubbling, and tread wear," he answered.

"Good. One of the most important things is called 'tread depth.' It measures how much your tires are wearing down by the grooves in the tire, here, see?"

Mr. Singer dug a fingernail into the treads of the Chevelle's tires.

"If your tires wear down too much, you can hydroplane on wet roads, or go into skids. Your traction is shot to hell. Now, a mechanic is gonna check your treads with a tread depth gauge." Mr. Singer pulled what looked like a large syringe from the pocket of his coveralls. "In most states, tires are legally worn out when they have worn down to 2/32 of an inch of remaining tread depth." He looked around at the class. "Maybe you wanna write that down?"

There was a flurry of activity while the students grabbed pens and notebooks from their bags.

"Now, to be safe, you need to have more tread depth than that. That's why you should replace tires when it gets down to 6/32. In the rain, replace them when it gets to 4/32."

"Uh, Mr. Singer, what if we don't have one of those measuring thingys?"

"Good question, uh — "

"Jo."

"Jo. I'm gonna show you what you do, unless someone here already knows."

Castiel looked around, but no one knew or seemed willing to answer, but then Dean stepped forward again.

"You use the change in your pocket."

"Right again, Winchester. Okay, we're gonna use a penny and a quarter."

Mr. Singer pulled out the coins, and handed the quarter to Dean to hold.

"Stick the penny in, upside down, first on the tails side, which shows the Lincoln Memorial. If the top of the Lincoln Memorial is always covered by the tread, you have more than 6/32 of an inch of tread depth remaining. Now, flip 'im over and stick ol' Lincoln's head in there, upside down. If part of Lincoln's head is always covered by the tread, you have more than 2/32. With the quarter, stick Mr. Washington in there upside down too, and if his head is always covered, you got yourself 4/32."

The class dutifully took notes, except Dean. Castiel figured if he was the one telling Mr. Singer the secrets to the coins in his pocket and tire wear, he didn't need to. Still, it seemed odd that one could measure how much a tire was wearing just by using a few coins. Despite writing it down in his notebook, Castiel remained unconvinced.

"The other good reason to check the treads often is 'cause sometimes stuff gets caught in there. A tack or a nail embedded in the treads is hard to see if you ain't lookin'. You'll never notice it until days or weeks later when you're stuck with a flat. That's why it's good practice to check your tires on occasion."

Mr. Singer stood back up and wiped his hands on his thighs. "Over there in the bucket is a bunch of tire treads. Each of you take one and find a benchtop. You can practice testin' the treads with the coins I hand out."

They all returned to their seats with pieces of tread torn from old tires and two coins each. Castiel looked around and was careful to find a stool at the far corner of the benchtop, out of everyone's — and especially Alastair's — way. He was struggling to stick Lincoln's head into the rubber when he felt someone sit across from him.

He glanced up to find Dean, who was rolling a quarter over his knuckles in a perfectly balanced wave from pinkie to forefinger. Back and forth, back and forth, and Castiel lost track of what he was doing because he was staring at Dean's fingers.

"I can do this with a baseball, too," Dean said.

"Are you...I'm sorry, were you addressing me?"

"There's no one else sittin' here, is there?"

"No," he answered, pulling his backpack closer.

"You have to make sure you push it into the tread with just enough force, but not so deep it gets stuck."

Castiel gestured at the piece of rubber in front of him. "This makes no sense. Using coins? It hardly seems like an accurate way to test a tire's wear."

"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy," Dean said. "Do you want some help?"

Impressed and surprised by Dean's recitation of the Hamlet quote, Castiel could only stare at him.

Dean reached over and grabbed Castiel's coin and the tire tread. He seated Lincoln into the rubber, and then took Castiel's hand and placed it on the penny.

"See? Feel that? Just enough. It doesn't replace checkin' with a gauge, but it'll let you know without havin' any tools around that you need new tires."

Castiel nodded, then frowned at the unrequested help. He took a quick glance to see if Alastair was putting Dean up to this, but surprisingly, he was talking with Brady and not paying Castiel any attention whatsoever.

When Castiel looked back Dean was smiling at him.

"Yes, thank you," Castiel said, still cautious. "I appreciate your assistance."

"Sure."

Dean flicked Castiel's penny back onto the benchtop and went to rejoin Alastair and his crew.