“It can’t be a coincidence that the four of us who suffer future shock end up dead,” Chris says. “Adam has to be involved somehow. He must have lied to us about what really happened.”

“Why would he do that?” Trent asks.

“If he’s working for them—”

“Guys, I’m standing right here,” Adam says.

As they argue, I rub my palms against my eyes and try to think. As much as I sometimes hate my perfect memory, I can’t imagine not remembering these hours of my life. I catch Adam watching me and realize that if Dr. Walters is right, I won’t remember Adam either. Probably for the best, really.

“I’m sorry I can’t help you more,” Dr. Walters says. “You seem like good kids. Very sad how it all turned out.”

Trent pulls back a curtain and peers out the window. “We should go. The police could be here any second.”

“Yeah,” Adam says. “Lynne’s address is probably in the car. Maybe she can help us.”

“Wait.” I know we need to hurry, but there’s one last thing I have to ask Dr. Walters. “Can the future be changed? Or is everything we’ve seen going to happen?”

“Somehow I’m not surprised you asked me this,” he says. I hold my breath, fearing he’ll blow my cover, but he relaxes back on his pillow and continues. “That’s one thing I hoped to study with the accelerator, but I was never able to prove anything one way or another.” His voice grows stronger as he slips back into the scientist role.

“One theory says everything is predetermined, which means everything you do once you return to the present will lead up to this future. Even if you think you’re changing something, you won’t be. But another theory says if you change something when you get back, the moment will split off and create an alternate timeline with a new future.”

“So if we go back and change something in the present, this future might be different?” I can’t even think about the other possibility—that nothing we do matters.

“Maybe. This future might still exist, but you would be living in another parallel timeline, based on the changes you made. Or maybe the future you went to, including this moment right now, would vanish entirely. It’s impossible to know.”

Everything we’ve heard from Future-Adam suggests that we’re living in a predetermined loop where it’s impossible to change the future. Otherwise, how would he know so much about what we’re going to do? But maybe we’re only visiting the timeline he’s lived through, the one in which we all die. If we go back now and change something in the present, maybe our future will be different.