A young couple, Gaspard (Grégoire Leprince-Ringuet) and Marion (Pauline Etienne) are enjoying summer in the idyllic South of France when, by chance, they find a mobile phone. Their curiosity is piqued by the mysterious tone of the messages on the phone – as well as by photographs of a beautiful woman stored on it – so they decide to go along to the meeting-place of a church suggested by ‘Dragon’ (Swann Arlaud) to ‘Sam’ (Louise Bourgoin). Having got a glimpse of the couple, they decide that following them further would be an interesting afternoon’s diversion. This doesn’t prove as easy or as e...