On an isolated Portuguese island, a nameless man makes a mental journey which brings him into contact with the strange and menacing world without peace and harmony.

A Noite de Walpurgis is a fantastic tale by Hugo Rocha, admittedly inspired by Goethe's Faust. The narrator-protagonist reveals a story told to him by a third person. Here the third person is an old peasant woman that the protagonist finds in a walk through the mountains, and that tells a story that in turn would have been told to her by the grandmother.

The film is inspired by the Mário de Sá-Carneiro short story, where the narration is made by Professor Antena's assistant who walks by his side when he is run over in a perhaps enigmatic way.