When Marine falls in love with Alex this relationship is destabilised, and Lisa takes a dislike to Alex. Their mother, Millie is the voice of reason as the two sisters struggle to come to terms with a new set of emotions.
Marine and Alex go through a bit of a bad patch but make up, only for tragedy to strike. With Marine hospitalised, and in a serious condition, Lisa and Alex gradually warm to each other, Alex becoming a sort of a father figure for Lisa's son, Léo, brilliantly played by Théodore Maquet-Foucher.
The film is presented as three stories, firstly Marine's, then Lisa's and then Alex's. It doesn't re-tell the same events three times over, but concentrates on each character individually during her or his critical period. This was Mélanie Laurent's (who plays Lisa) first director's role, and the critical reviews were mixed. But given that women need to be ten times better than men to garner equivalent praise, it's perhaps not surprising that a young actress turned director would find it hard to please the critics. Personally I found the film to be delicate, quite beautiful in fact, with some nice cinematic touches and convincing performances from the cast.