'Cuca Legal' tells the story of Mário Barroso, a single aviator involved with three women at the same time: Virgínia, Irene, and Fátima. Virgínia is a wealthy businesswoman obsessed with the direction of her late father's business; Irene is a middle-class young woman who gives private piano lessons; and Fátima is a poor widow. Mário can't decide which of them is the ideal woman to give him a child with a "cool head" (cuca legal). Things get even more complicated when Maria Joaquina, nicknamed Kinu, Virgínia's mother, also catches the aviator's attention. To escape the troubles he constantly gets into, Mário relies on the help of his mother, Dalva, and Jacaré, his great friend.