Léonard has a small problem: his disciple has chickenpox. He must find someone else to test his inventions, and unfortunately Mathurine refuses to take care of it. Things start again when the disciple recovers, and the genius can again invent. He invents among other things the expresso, the glue, the fan, the snow cannon and many others. However, a conflict with his disciple regarding the name of the cat. Should he be called Raoul or Prosper? And if it was the cat that chose. In short, the life of our genius is still so agitated.