The real monster is a terrible serial killer who rapes women and has just escaped from the authorities. But the police suspects innocent Window Dresser Loris (played by actor, producer and director Roberto Benigni), thanks to his unfortunate habit of being caught in compromising situations. It is true that Loris is a compulsive liar, but when faced with Jessica (Nicoletta Braschi), an undercover policewoman who is trying to seduce him in order to confirm that he is in fact the murderer, will he reveal a different side? Il Mostro was a huge box-office success (the highest revenue ever for an Italian film in Italy), allowing Benigni to make his next film, Life is Beautiful.