If We Never End by Laura Taylor Namey

You’ve Reached Sam meets If I Stay in this epic romance spanning life and death, from New York Times bestselling author Laura Taylor Namey.

Sylvie Castellano is used to goodbyes. Every summer, her friends leave to vacation at faraway beaches and her parents jet off to work on a luxury yacht, dumping her with her tia Vivian. Sylvie may love her aunt Viv, but just once, she wishes the summer held a big adventure for her, too.
When Sylvie scores the thrift find of a lifetime-a vintage gold watch worth thousands-she thinks maybe her luck is turning around. Then a turn of the watch’s dial summons a ghost boy. With no idea who he is or why he’s attached to the watch, and only his name to go off of-Penn-Sylvie offers to help him unravel the mystery of his death.
Sylvie’s summer is suddenly full of road trips, beach bonfires, and ferris wheel rides as she and Penn try to piece together the life he lost. But soon, Sylvie begins to imagine a future together-a future they can never have. Then a devastating discovery brings everything crashing down. The watch’s secrets extend far beyond Penn, and it’s not only Sylvie’s heart at risk, but her life.