Colette is a former military nurse and a lively octogenarian. She shares a large Parisian apartment with her sister Maryvonne, a former teacher. Those two fiery tempers are totally opposed since their childhood but have nevertheless forged an inseparable pairing . A long stay in the countryside leads them to entrust their apartment to Maryvonne's granddaughter, Julie, a cellist with a sweetheart. As Julie moves in the apartment, she soon meets, near the barge where she plays every night, Victor, a lost kid and his homeless father François.