In Lille, Claire Gauthier is an ordinary married woman with a young daughter that works in an insurance company analyzing losses of insured properties. When the single veterinary Laurent Kessler claims damage in his basement caused by a flooding due to water leakage, Claire resolves the situation favorably for him. The weird Laurent visits Claire in her office successively, inviting her for drinks and lunch, and they get close to each other. Meanwhile, a serial killer is terrorizing Lille, killing women with a scalpel. Claire feels a great attraction for Laurent, who has an unusual behavior in her apartment. When Claire sees a scalpel in the pocket of Laurent's jacket, she fears him, but still loves him.