It’s the first day of the holidays and Sam is roaming the island of Texel, imagining what it’d feel like to be the last person on earth. Then, like a whirlwind, 12-year-old islander Tess swoops into his life. Sam’s only option is to go along for the ride.

Soon he’s dancing the waltz, burying a pet canary and coming up with an especially weird plan to help Tess find her father, who doesn’t even know she exists. Along the way, Sam discovers the true meaning of family and what it is to...