Montmartre, 1885. Under construction, the Sacré-Coeur takes shape on the Butte.
Séraphine, aged 13, leads a monotonous life at Jeanne’s home, the grumpy seamstress who raised her. She has an obsession: to find out who her parents were. With her faithful sidekick Mistigri, a street kid she takes under her wing; worming bits of her story out of Charlotte, her eccentric aunt, Jules the priest, Raoul the painter or a whimsical homosexual couple, regulars at the cabaret where she works, Séraphine pieces together the secret of her origins. She goes in search of her father, who’s close to Louise Michel, heroine of the Paris Commune.
Séraphine’s destiny will then take an unexpected turn.