Told to explain how Yayati came to marry Shukra's daughter. The gods, losing to Asuras whom Shukra keeps reviving, send Kacha to become Shukra's pupil and to please Devayani. He serves both for five hundred years before the Asuras kill him: first cut up and given to wolves and jackals, then ground to paste in the ocean, then burnt and given to Shukra in wine. Each time Devayani pleads and Shukra calls him. The third time Kacha answers from inside the teacher, receives the science there, tears his way out and revives Shukra, who then bans wine for brahmins. At the end of the vow Devayani proposes; Kacha refuses; the two exchange curses, and he goes home to the gods' welcome.
Tagore's verse drama (Bengal), in his English version
East India · BengalAll traditions
Tagore keeps only the farewell. Kacha asks leave to go; Devayani asks whether he wants nothing more and walks him through what he is leaving: the banyan that shaded him when he grazed the cattle, the river Venumati, the day he first stood at the garden hedge and offered to help her gather flowers. He offers gratitude for being revived three times; she rejects the word and says she knows he loves her. He admits a secret devotion but will keep his promise to the gods, though heaven will no longer be heaven to him. She curses his knowledge to be a burden never lightened by sharing. The English text ends on her curse.
What is different here:
Only the parting is shown. Kacha confesses love instead of calling her sister; there is no counter-curse in the English version; the banyan, the river Venumati and the first meeting are Tagore's.
Sources: The Mahabharata, tr. K. M. Ganguli (1883-96), sections read for the Vedic layer; The Fugitive, Rabindranath Tagore (1921): 'Kacha and Devayani'