It's summer and it's hot in Montreal, and we meet many people: Rita, the nice homeless girl, who moves to Roxan's house; Henriette, who falls in love with her neighbour, Lloyd, the sexual-obsessed radio host, and a young couple, Marc and Loulou, whose relationship is in danger because of Loulou's affair with Lloyd, and many more, as the summer becomes hotter and hotter...

Karmina, a young vampire (only 140 years old) flees her Translylvanian castle where she must marry the horrible Vlad to please her father, the mean Baron, and her mother, the eccentric Baronness. Karmina finds refuge in Quebec at the home of her aunt Esméralda, an older vampire who lives among humans thanks to a potion that temporarily transforms a vampire into one of them. Under the effect of the potion, Karmina falls in love with Phillipe, a charming church organist. But Vlad, the Baron and the Baronness soon show up in pursuit of her and turn a poor customs officer, Ghislain Chabot, into a vampire to aid them in retrieving her. Esméralda must become the great vampire of yesteryear to fly to the aid of the lovers.