Zé Alberto and Laura are lovers, and have a clandestine and permanently threatened relationship. Zé Alberto is married to Fernanda, Laura's sister, whose husband is in prison for murder. Fernanda is aware of Laura's relationship with her husband and constantly threatens them to tell Armando everything. Laura and Armando have a daughter - Sónia - whose greatest defect is greediness and the highest quality to cover up her mother's romance with her uncle. The fear of the two lovers increases and events precipitate when they receive the news that Armando is about to go on parole ...
João and Jaime work as taxi drivers for the same company. But, once the company's vault is robbed by Raul, the manager's son, João is the one to blame.
En martes y trece, dos parejas deciden casarse sin temer a las supersticiones. Pero el caso es que a uno de los novios, antes de salir para la iglesia, se le incendia la casa. Una de tantas comedias que el director Pedro Lazaga realizó durante el franquismo. En ella vuelven a repetirse las situaciones habituales en este tipo de filmes, como son las dudas de una pareja de novios, las confusiones o los equívocos. Lo mejor, sin duda, el trabajo de los actores, especialistas en el género como José Luis López Vázquez o Concha Velasco.
