Aurelio Milano (Michelangelo Pulci) is a 30-year old electrician who comes up with a gadget that can change people's behaviour. He presents himself to the woman he loves, his next-door neighbour Chiara (Chiara Muti) as a famous scientist. Chiara is a beautiful woman who has never even noticed Aurelio, -Chiara is determined to become the mayor of Genoa. Aurelio tries out his invention on three guinea pigs, three penniless taxi-drivers called Giotto (Alessandro Bianchi), Gilberto (Filippo Lamberti) and Costantino (Claudio ìNocera), with help from his assistants Angelo (Andrea Di Marco) and Vincenzo (Paolo Passano) and a woman friend called Romana (Barbara Tabita). The machine works.
Aurelio speaks to the ghost of his father Tolomeo (Gino Paoli) and decides to use the machine to convince Chiara that she is madly in love with Aurelio.
In the meantime the effects of the machine run out and the three taxi-drivers go back to being aggressive, violent and anxious. Chiara and Aurelio make love. She wakes up and slaps him and runs away...