When a body is found in the ghost train of the Palavas-les-Flots fair, Sandrine Laplace, a zealous meter maid, decides to lead an investigation, unbeknownst to her higher-ups. Even if that means putting herself in danger.

Undercover among the carnies, Sandrine finds herself embroiled and strays further from the law. Now linked to Yvanne and Carmen through a dark secret, there's no turning back.

Disturbing events multiply. Yvanne descends into paranoia. Her relationship with Carmen, growing ever tense, makes Sandrine question all her theories. Meanwhile, Carmen finds herself in danger.