At the beginning of the 19th century, in the countryside, a duchess suddenly finds herself in a very delicate position: pregnant by her lover while married to a duke she hasn't seen for 15 years. When he comes to visit her late at night, the duchess considers the worst.

An actress is about to play the part of Mariana Alcoforado, a young nun from the convent of Beja who was writing five letters to her French lover, the officer De Chamilly. The actress, being the perfect embodiment of Mariana, will drive us to a journey beyond time and imagination.