The gods know I’ve tried everything else. I’ve petitioned Olympus, scoured the legal section of the library, even asked Headmaster Petrolas for advice. The answer was always the same: the decree is irreversible without a unanimous Olympic vote. Hera will never vote in our favor.

If I want to unbanish my parents and bring Griffin’s back to him, I have to try.

“My only chance to make things right,” I say, “is to go back and stop it from happening in the first place.”

Phoebe stares at me for a long time. Like, an insanely long time. I can’t read her thoughts—I mean, I could use psychospection if I really wanted to, but that’s rude. Instead, I wait for her to finally speak.

“Changing the past,” she says. “Isn’t that dangerous? Wouldn’t you risk, like, unmaking yourself?”

“I would already be born,” I argue.

“But other things,” she insists. “You could screw up whole time lines that depend on that event happening. My mom used to love this old movie about a time-traveling car and—”

“There are fail-safes.” Troy points at the book. “According to the text, existing time lines are inviolable. Changing something in the past changes it now, but it still happened then.”

“What does that even mean?” I demand.

“I know, I had to read it three times to understand,” he says. “But basically, the primordial gods—the ones responsible for all the laws of nature and physics—didn’t want time travel to break the space-time continuum. They ensured that going back can’t change anything that happened between now and then. Only what happens from now on.”

I shake my head. I swear, that boy has too much book learning sometimes.

“You’re sure?” Phoebe asks, and I can tell she is really concerned that I will destroy the universe by chronoporting.

“I’m sure,” Troy promises.

“Think of it this way,” I say. “Why would the gods create a power that could unmake all their hard work?”

She considers that for a moment, studies both me and Troy like she’s judging how much we believe what we’re saying, and then finally relaxes her shoulders.

“This is insane.” She waves the book in the air. “Time travel?”

“I know.”

I try to snatch the book back from her, but she waves it out of reach.

“That’s why I don’t want anyone else involved,” I explain. “It’s too dangerous.”

“Troy’s involved,” Phoebe argues.

I roll my eyes. “Like I could stop him.”

Phoebe grins. “Well, you can’t stop me, either.”

“Thank goodness,” Troy cheers and collapses onto my bed.

“You don’t have to do this,” I tell Phoebe.

“I know,” she replies. “But I’m going to.”

She sets the book on my desk as she stands, and then pulls me into a hug.

“For you,” she whispers, “and for Griffin.”