France, 1760. Marianne (Noémie Merlant) is commissioned to paint the wedding portrait of Héloïse (Adèle Haenel), a young woman who has just left the convent. Because she is a reluctant bride-to-be, Marianne arrives under the guise of companionship, observing Héloïse by day and secretly painting her by firelight at night. As the two women orbit one another, intimacy and attraction grow as they share Héloïse’s first moments of freedom. Héloïse's portrait soon becomes a collaborative act of and testament to their love.