From the award-winning author of The Probability of Everything, which has been called "one of the best books I have read this year (maybe ever)" (Colby Sharp, Nerdy Book Club) and "Powerful" (Kirkus Reviews, starred review), comes a heartfelt exploration of family and change as twelve-year-old Skye reunites with her older brother, Finn, after he spent four years on the run with their father.

Skye Nickson's world changed forever when her dad went on the run with her brother, Finn. It's been four years without Finn's jokes, four years without her father's old soul music, and four years of Skye filling in as Rent-a-Finn on his MIA birthdays for their mom. Finn's birthday is always difficult, but at least Skye has her best friends, Reece and Jax, to lean on, even if Reece has started acting too cool for them.

But this year is different because after Finn's birthday, they get a call that he's finally been found. Tall, quiet, and secretive, this Finn is nothing like the brother she grew up with. He keeps taking late-night phone calls and losing his new expensive gifts, and he doesn't seem to remember any of their inside jokes or secrets.

As Skye tries to make sense of it all through the lens of her old Polaroid camera, she starts to wonder: Could this Finn be someone else entirely? And if everyone else has changed, does it mean that Skye has to change too?