Christina Lauren, the New York Times bestselling author of The Paradise Problem and Love and Other Words, returns with a sweeping romance about first love, second chances, and the one summer that changes everything about both.

Frankie Flowers and Bobby Falco have spent most of their lives trying to outdo each other.

As neighbors turned academic rivals, they grew up competing over everything. Somewhere along the way, rivalry became friendship, friendship became love, and then, at eighteen, everything between them fell apart.

Eleven years later, Frankie has built the exact life she once dreamed of—far away from her tiny hometown. She’s successful, independent, and has perfected the art of not looking back. But when she finally returns to Lake Himmel for the summer, she discovers that some things haven’t changed nearly as much as she'd like.

The lake is still there. The house next door is still there. And so is Bobby Falco.

Bobby is no longer the boy Frankie remembers, but being around him still feels dangerously familiar: the competition, the banter, the uncanny way he sees straight through her. And as old feelings resurface, Frankie begins to wonder if the one thing more dangerous than their old rivalry is discovering what really ended it.