Sam must deal with his friends' inexplicable disappearance.

Victor and Romane must learn to live with Samuel and Bilal's disappearance.

Four years later, Victor tries to persuade Romane to follow his plan to send them both back in time.

Romane and Victor get a shock when they go back in time to the world they used to live in.

Sofia tries to fathom the secrets of interdimensional travel.

Retz and Sofia have devised a strategy. But nothing goes to plan.