Content Warning: This section of the guide includes discussion of death and child death.

Cassidy Blake is heading to Paris. She’s on summer break and is accompanying her parents as they visit the world’s most haunted cities for a reality show they’re filming. The family cat, Grim, is traveling with them, as well as Cassidy’s best friend, Jacob, who happens to be a ghost. A year ago, Cassidy nearly drowned in the river, but Jacob saved her and brought her back from the brink of death. Ever since, he can read her mind, and she can cross into the realm of restless spirits known as the Veil. Cassidy’s job is to help these spirits move on. She learned this from Lara Chowdhury, a girl she recently befriended in Scotland who has the same gift. Lara calls people like her and Cassidy “in-betweeners.” 

Lara doesn’t believe in letting ghosts stay behind where they no longer belong, even Jacob. Naturally, the two don’t get along. Cassidy’s vintage camera fell into the river with her, and now it also has a special ability. It works beyond the Veil, capturing glimpses of that other world. A faint reflection of Jacob in one of its photos shows that he’s getting stronger and more able to interact with the physical world.