Sam must deal with his friends' inexplicable disappearance.
Victor and Romane need to learn to live with Samuel and Bilal's disappearance; Victor finds difficulty connecting with his parents after they seem to blame him for Sam's disappearance.
Four years later, Victor tries to persuade Romane to follow his plan to send them both back in time; Bilal gets snippets of memories of his "former life," but they remain too vague to make any sense.
Romane and Victor receive a shock when they go back in time to a world they used to live in; Victor feels extremely bitter towards his parents, whereas Romane, overwhelmed with sadness, decides to try to comfort her mother.
Sofia tries to learn the secrets of interdimensional travel; Victor becomes a loner; feeling outcast, Samuel tries his hardest to fit into the group of friends; Sofia conducts a new experiment in the bunker.
Retz and Sofia try to devise a strategy, but nothing goes according to plan; Sofia realises that she has to jog Bilal's memory, as only he holds the knowledge she needs to make the interdimensional journey a success.
Thomas Chomel
Samuel "Sam" Deslandes
Jules Houplain
Victor Deslandes (17 ans)
Maxime Bergeron
Victor Deslandes (13 ans)
Omar Mebrouk
Bilal Belkebirs (30 ans)
Timoté Rigault
Bilal Belkebirs (14 ans)