Anne, an attorney advocating for abused minors, enjoys an enviable lifestyle with her husband, Pierre, a milquetoast businessman and ineffectual father to Théo, his troubled teenage son from a previous marriage. Compelled by her stepson's Apollonian beauty, Anne embarks on an affair that threatens the stability of her household, along with her professional integrity, as she faces a choice between accountability and deception. Théo is a fragile figure, and as time passes, the relationship turns destructive.