Pepe, no me des tormento (1981)

Mario has to write a screenplay for a movie and calls his friend Pepe, a weird collaborator. Mario lives with Bárbara, a divorced American, and his 3 sons, but in his house he can't write. That's why he decides to go with Pepe to a friend's house to write the screenplay. But there they find a bank thief who knows Pepe from a previous "business".