Charles is a happily married man with a sickly child that he dotes on. Unfortunately this fails to prevent him from embarking on an affair with the "she may not be as sweet as she seems" Lucinda. This act of infidelity in turn attracts the attention of psychotic thief Phillipe who, after a violent encounter, proceeds to blackmail Charles. Derailed swiftly descends into the world of the preposterous thriller, replete with devastating ‘twist', but it is not without undemanding appeal and is surprisingly dark.