Haunted by the brutal trauma of her recent combat deployment, a highly trained French soldier, Olga Kurylenko, is transferred home to the coastal city of Nice to serve as a "Sentinelle." Her duty is to patrol and protect, but a personal mission of vengeance erupts when her younger sister is violently attacked. Blending her lethal military skills with a desperate, singular focus, she plunges into the city's treacherous underworld, defying her commanding officers and the local police. As she tracks the perpetrators, the line between soldier and vigilante blurs in this tense, R-rated action-thriller directed by Julien Leclercq. With each step closer to the truth, she must confront not only a dangerous criminal network but also the psychological scars of war that threaten to consume her entirely.