This gritty crime drama set in the dark underbelly of Paris follows police officers and lawyers as they investigate and prosecute crimes. Throw any romantic notion of Paris out the window. Crime is dark. The legal system is darker. This is Spiral.

Vigilante, a small armored truck company, is in full crisis mode. Victim of three violent hold-ups in a year, which left no survivors, the company is on the verge of bankruptcy and its employees are extremely worried. Some even suggest a complicity between the robbers and the firm. It is in this difficult context that a man, Alexandre Demarre, one morning presents himself to start his first day of work at Vigilante.

After a year of separation, Antoine decides to go to his former girlfriend Julie, as if they had never left. Antoine will do everything to seduce Julie again, despite their breakup.