Waterbomb for the Fat Tomcat

The two sisters' parents have gone abroad to earn the living, so the girls Marta and Linda needs someone to take care of them. For that they have their dictatorial spinster aunt Una, who desperately wants to get married, and has a sympathy for the jeweler Ivo. Meanwhile, Marta is working hard to get a promised puppy, but her plans are ruined, as her aunt feels a strong despise for dogs. So, the relations between the girls and their aunt becomes really tense. Until the perfect plan of the sisters - to help the aunt to get married, to get rid of her.