It is named after the hall of mysteries located in the residential part of the building, which faces the sea. A large continuous fresco that covers three walls, one of the most preserved ancient paintings, depicts a mysterious rite, that is reserved for the devotees of the cult. The scene is linked with Dionysus, who appears on the central wall with his wife, Ariadne.

Female figures as well as fauns, maenads and winged figures are seen on the side walls, engaged in various ritual activities. Besides Dionysian ecstasy expressed in dancing and drinking wine, one sees the ritual flagellation of a young girl resting on the lap of a seated woman (bottom right). The other rooms also preserve wonderful examples of second style wall decoration, that is with depictions of architecture. Egyptian inspired miniature paintings are seen in the tablinum.

The villa also includes an area intended for the production of wine with a rebuilt wooden press. The complex dates back to the 2nd century BC but was given its current shape in 80-70 BC, which is the same period of the frieze of the mysteries.

Date of excavation: 1909-1910; 1929-1930.