Never 2 without 3

One evening, Etienne, a police officer from the BAC, and Christian, his teammate, witness the assault of a young girl. But the killer manages to escape, seriously injuring Christian. Shortly after, Etienne discovers, on the one hand, that Angèle, the woman who left him seven months earlier, is about to give birth and that his new boss, Alex Le Guen, is none other than the man he spent the night with after a drunken evening.