Step two: Ask a question.

Can I time-travel to save Mabel? Can I save Mabel with science?

I flip back through my notebook. I reread the words of the MIT scientist. Time travel is possible. It’s very likely someone has already done it.

Possible. Someone has already done it. My brain soaks up those words like a sponge. They are the proof I need to keep going.

Step three: Form your hypothesis.

I know as well as anyone that the success of a science experiment depends upon the hypothesis. A good hypothesis should include a couple of things. It must explain what you are going to test, and it also must set the scope for the project. Hypotheses help you to be organized, and they let you know what to expect from an experiment. They’re also how you measure whether or not your experiment is successful.

Past hypotheses I’ve written have read like—

If we don’t water our class plant, it will not grow.

If I drop the pennies in the lemon juice, they will become shinier.

If I launch a marble and a Ping-Pong ball from the same catapult, the Ping-Pong ball will travel farther.

Sometimes my hypotheses were right. Sometimes they were wrong. But it was okay no matter what. Those were simple experiments, though. This is not a simple experiment.

This time my hypothesis has to be right. It has to be perfect.

Sixteen

Quinn

Dear Parker,

Mom and Dad are still fighting every night. It makes me so sad to hear them argue. Mom thinks what you did is all Dad’s fault. Dad thinks it’s the fault of all the things you read on your computer.

I don’t know what to think.

Actually, I do.

I think it was your fault.

Your sister,

Quinn

When I get the text from Cora telling me to meet her after school, I almost can’t believe it. But when I walk to the side of the athletic field, she’s already there, sitting on a bench, waiting for me.

“You’re late,” she says. She’s wearing a knitted beanie over her dark curls and is looking down at a notebook that’s spread out over her lap.

“School just let out.”

“Ten minutes ago.”

I swallow. “I waited in the library for the halls to clear out.”

Her lips move like she’s about to comment on that, but she doesn’t. I rock back and forth on the balls of my feet and wait for her to say something. Anything.

“Aren’t you going to ask me why I wanted to meet?” Cora doesn’t look up from her notebook. She also doesn’t offer me the seat next to her, so I stay standing.

“I—I—I—” A Freeze-Up. Great.

She finally looks up and blinks at me.

I blink back at her. Twice. Freezing Up, but okay.

“I think you might be right,” she says. “About time-traveling.”

My heart cartwheels.

“At first, I thought this was silly make-believe stuff. Like the things you were into when we were little,” Cora says.