Roger tells Fatou a joke and it’s a really stupid joke because Roger can’t tell it right and it’s really embarrassing for Fatou because she really doesn’t dare tell her friend that he is a terrible joke teller. Still, Roger is aware of his shortcomings and is sorry, he knows he blew it. He would like so much to make Fatou laugh with a good joke, kind of like Igor does. So he decides to take joke-telling lessons with Igor, since Igor is apparently the king of jokes. But it backfires, Roger is still way too serious! But still determined to make Fatou laugh at one of his jokes, the alien decides that science is the solution. He invents a laughter ray which accompanies his jokes and it turns out to work pretty well. In fact so well that Irina, who is inadvertently struck by the ray, can’t stop laughing herself...to the point of endangering her life...!