Four weeks after giving premature birth to Romy, still in an incubator at the hospital, Laure Berthaud is eager to resume service. The 2nd DPJ is called in the twentieth arrondissement where a human torso was discovered. Arnaud Beckriche, the new Commissioner, overseeing the investigation, leaves a week to his team to solve the case before transferring it to the criminal brigade. For her part, Josephine languishes in a firm specializing in business law when Eric Edelman comes to offer to defend the son of a famous cosmetic surgeon, accused of having ordered the murder of his father.