DeLano, L. E.

You're still you no matter where you go. Jessa has learned the hard way that traveling to alternate dimensions isn't all delicious, glittering desserts and fancy parties: it also means accidentally running into people she thought she'd never see again. Still mourning a devastating loss, Jessa isn't really prepared for the arrival of a reckless version of someone she once loved who is now bent on revenge.

Teen author Jessa learns that she and one of her characters, Finn, are Travelers with the ability to slide between realities, and that Finn is determined to prevent her dying in yet another realm.