Marc is an intern in the prestigious neuroscience lab of Professor Georges Erwin. He is working on an experiment that enables to make people laugh, and, in term, maybe to control one's emotions. He has met Elsa, a first year student in the school where he works. The young woman troubles him. One night, he offers her to try his device, but she starts crying instead of laughing... Bewildered and embarrassed, he does not know if he should report this unusual reaction to his professor. And that is when he discovers that Elsa has a tumultuous and secret relationship with the eminent George Erwin...