Queen Semiramide is haunted by the ghosts of her past. Together with her lover Assur, she once murdered her husband King Nino; a deed which ever since has weighed heavily upon her. With her marriage to Arsace, she hopes her soul will at last find solace. Her love, however, is misplaced. Arsace not only loves another, he is also, as is later revealed, the son Semiramide and Nino believed to be dead. He is faced with a decision: should he avenge the death of his father – and thus become his mother's killer?

A couple and their hallucinatory journey to the dark side of passion. Renata is driven by a longing for the consummate sexual encounter. Since her youth she has had a vision of an ecstatic conjugation with a shining angel. Ruprecht falls for Renata and follows her unreservedly on her obsessive quest to fulfil this fantasy. The couple cross the boundaries of perception, leaving behind all traces of morality or reason, until their willingness to devote body and soul completely to one another threatens to pull their previous existence apart.