Nadine Legrand and Patrick Bissonnette begin their first day in the District 31 neighborhood station, under a policy aimed at bringing investigators closer to the population. It is also a special day for Nadine as it marks the 20th anniversary of the death of her father, a police officer killed on duty. Commander Daniel Chiasson welcomes his new team, while detective sergeant Laurent Cloutier transmits his instructions to the investigators he leads. Patrick and Nadine must try to find an eight-year-old boy, Théo, who disappeared with his skateboard. They meet the parents, Florence and Alexandre. Kevin Nadeau, Nadine's partner, surprises her by announcing that everything is over between them.