Clem follows the life of a young teenager, Clémentine, who becomes a mother at the age of sixteen, at the centre of tensions between her parents and Julien, the father of her child Valentin. It deals with the problems of teenage life and that of a mother with a strong personality.

Four teenagers' lives are turned upside down when a mysterious event propels them into parallel dimensions.

Claire lost her husband Gabriel during the tsunami in 2004. His body was never found. 15 years later, Claire has a new life with Lukas and her son Zack. After a decade of mourning and professional purgatory, she has just landed a dream job in Abu Dhabi. One night, Claire is having dinner and sees Gabriel's reflection in a window.