Lyon, present day. When widowed marine biologist Abel learns that his impulsive mother Sylvie is once again re-marrying – this time to an inmate she met whilst teaching theatre in prison – he’s more than uncomfortable. Doubting that convicted burglar Michel is capable of staying out of trouble, Abel’s protective streak kicks in, and with the help of his best friend Clémence, he begins tailing his new stepfather’s movements. Their amateur sleuthing is quickly uncovered by Michel and triggers an unlikely – and bold - business proposition for them both…