Thomas Mann subtitled the novella An Indian Legend as the story is based on an old folk tale from India.
Two friends Nanda and Shridaman see the lovely Sita bathing in a local pool and each of them falls in love with her. She marries Shridaman and has a child with him, but she also loves Nanda, so there is a love triangle in operation within the story.
Six months after the wedding, the married couple set off to visit her parents accompanied by Nanda. On the way they stop at a temple to the goddess Kali where Shridaman goes to pray. In a fit of religious fervour, he commits suicide by chopping off his own head. When Nanda finds Shridaman in this state, he is bereft and does the same thing.
The goddess Kali appears to Sita and informs her what to do to bring them both back to life. The title of the book tells you what happens and the ending is traditional though still shocking.