Since their parents died in a car crash, Alice has had to become more of a mother to Flick – a responsibility that traps them both and heightens their love-hate relationship. Resigned to the way things are, Flick determines to expect nothing exceptional from life and give little in return. She is forced to re-evaluate, however, when one day she steps through the wrong doorway and finds herself trapped in the space between parallel worlds; the place known as The In-Between. There she is met by the mysterious, if slightly nerdy, Guide Calicus; a young man who has spent his entire life leading people between worlds. He offers Flick the chance to leave her problems behind and journey to another world and, as he leads her through the In-Between, the two begin to form a close bond, causing him to wonder what it would be like to live a life of his own.