"Where She Went" by Gayle Forman is a sequel to Forman's previous young adult novel "If I Stay." "Where She Went" picks up three years after the conclusion of the first book. It tells the story leading up to the reunion of the main characters, Adam and Mia.
Adam and Mia went their separate ways at the end of the first book, and their lives have become drastically different in the years since. Mia is a star cellist and graduate of Julliard, and Adam's rock band has become wildly popular, thanks in part to the lyrics he wrote in the wake of their breakup. Mia is living in New York City, and coincidence brings Adam there by himself. The two reunite and spend one night together exploring the city and reminiscing about old times. The two are forced to revisit the past feelings of grief that divided them after the car accident that killed Mia's family in the first novel. Throughout the night, the two of them undergo a transformation that takes them away from their new lives and back towards the way they were before, when their mutual love of music brought them together in the first place. The old feelings of love return as they look to their future, possibly together.