Fortunately, I am a pro at secretly checking my phone. A text bubbles onto my screen.

Ten minutes. Don’t let Bryce get there first.

Shreya, my co-conspirator on Prom Council, has a special loathing for Bryce, who is inoffensively bland most of the time but stubbornly old school about prom. She wants us in Mrs. Somboon-Fox’s office first so we can get her good and buttered up.

The class discussion has switched gears to time travel. A debate has erupted over why Hank doesn’t go back to his own time, considering he’s so critical of the sixth century. One camp argues that he can’t; he didn’t plan his arrival there, so there’s no way to plan a return. The other camp argues that he never wants to go back because he’s made himself a legend with his “inventions” (which are really just DIY versions of things from his day).

“How many of you would stay in a past time if you had more knowledge than everyone else?”

Only two hands go up. Ms. Silverthorn can’t be surprised at our response: there’s no chance a generation raised watching HD movies on our phones is going to sign up for using torches for light or whatever.

Five minutes.

Shreya is relentless. I admire that. Maybe I should very discreetly text back—

“Would you like to add something, Luis?” Ms. Silverthorn stops me before I can type a syllable. I’m busted, but I fake it as if I’m engaged with this riveting discussion.

“I think Twain is being lazy. He didn’t even have a logic for time travel—it was just a device to get Hank somewhere he could shock everyone with trains and gunpowder.”

“Interesting,” she murmurs, which is teacher speak for wrong and I know where she’s going to go. We’ve already discussed every time travel movie ever made and she has a deep well of theories, so I know how to get her going. “Connecticut Yankee was the first novel to use a device now called a ‘time slip,’ a time travel method harder to control than either the portals or time machines of later fiction.”

Two minutes.

I almost leap from my seat. I’ll never beat Bryce. I eyeball the door and, without breaking cadence, Ms. Silverthorn nods that I can go. Cheng gives me a look that counts as a kiss for luck, and Nix gives me a look that says, “Don’t leave me here.” I race out, sure to be late, bound by the actual laws of time and space.