“Well, not just a fighter pilot. I’ll hopefully get to be a test pilot, and obviously I’ll do what Nate’s doing—astronautical engineering. Dad says … said … I can sneak in a PhD in physics, but I don’t know.”

“Okay. Wait. You want to test the planes? Correct me if I’m wrong: That does involve forcing a fighter jet into uncontrolled spins at, like, Mach Two, and then hoping you can get them back under control before you land, right?”

I nod. “Mach Three, some of them. Depends on the model. It’s not really much crazier than strapping yourself to a bomb and flying into space.”

He laughs. “I dig your logic. Although, I feel the need to point out that there’s no danger in your equation.”

“Danger isn’t a variable in any equation—the math would never check out. It’s unquantifiable.”

This makes him smile, which makes me consider the possibility that certain kinds of dangers, especially ones involving manga-character doppelgängers, actually are quantifiable.

“What’s your favorite thing you don’t know?” I ask.

“Right now? You.”

I cover my face and groan.

“Too slick?” he says, and I can hear his smile getting bigger.

“Yes.”

“Fair enough.”

Nate should be back. I have a sneaking suspicion he’s taking twenty years to look for chips on purpose.

I stop covering my face and look up at Ben, and looking at him makes me feel like I’m back at space camp, in the tank, weightless, all the air sucked out. But also like my feet are on solid ground.

“You know what’s really crazy?” I say, because I can’t stop myself, because I want to tell this mystery in front of me about the biggest mystery of all.

He scoots closer. “Hm?”

“That all the matter and energy that formed the whole universe as we know it was once smaller than a marble. The size of an atom. Doesn’t it make your mind COMBUST imagining holding the ENTIRE universe in the palm of your hand?”

Maybe I would say more, except my eyes hit his eyes and for a second we just stare at each other.

“I’m in so much trouble,” he breathes.

I blink. “What?”

Glass shatters in the kitchen, and I’m on my feet in a nanosecond as my sister’s angry snarl cuts through the swinging door.

“Jesus Christ, Nate, get off me.”

I bolt.

Toward my sister, away from—oh god, what just happened? What is happening?

I push open the door and stare. A supernova has exploded on the kitchen floor, an eruption of waves of hair and a red dress and bourbon and shards of glass, skin and flecks of chipped black nail polish.

Nate is staring down at Nah as though she is an equation he can’t possibly work out, and maybe she is. My sister is a mystery I will never solve.