The nymph Urvashi lives with the mortal king Pururavas on a condition; the Gandharvas make him break it, she vanishes, and he finds her as a water bird at Kurukshetra. The endings differ from text to text.
The Brahmana frames fifteen verses of the Rigveda dialogue in a prose story. Urvashi sets her terms; the Gandharvas steal a ewe's two lambs from her bedside; the king leaps up without his robe, lightning shows him, and she is gone. He finds her among bird-shaped nymphs on a lotus lake in Kurukshetra. After the quoted exchange she relents: one night at the year's end, in a golden palace. The Gandharvas grant his wish to be one of them through a fire kindled with two sticks of ashvattha wood.
A dialogue of eighteen verses with no narrative frame. Pururavas asks his wife to stay and talk; she answers that she has gone like the first dawn and is as hard to catch as the wind. He threatens to wander off and die among wolves; she tells him not to die and says that friendship with women does not last. She recalls four autumns among mortals living on a little ghee, speaks of the son who will be born, and the closing verse promises him joy in heaven while his sons offer to the gods.
What is different here:
No lambs, lightning or lake birds are narrated; no condition is stated; there is no reunion on earth and no fire-sticks. The hymn ends with a promise of heaven.
Urvashi comes to earth under a curse of Mitra and Varuna and marries Pururavas, son of Budha and Ila, on three terms: her two rams stay by the bed, she never sees him undressed, and she eats only ghee. After sixty-one thousand years the Gandharvas send Vishvavasu to take the rams. The king hesitates at the first theft and runs out with his sword at the second; lightning ends the marriage. At Kurukshetra she promises yearly meetings and bears five sons. A vessel of fire given by the Gandharvas turns into an ashvattha growing from a sami; from their wood he kindles fire, makes it threefold and reaches the Gandharva world for good.
What is different here:
Adds the opening curse, the ghee condition, rams instead of lambs, Vishvavasu by name, the long span of years, five sons and yearly meetings; sticks of ashvattha and sami measured by the Gayatri; Pururavas as founder of the three fires.
A five-act play. Pururavas rescues Urvashi and her friend from a demon and they fall in love. She drops him a verse on a birch leaf, which the queen finds. Acting in heaven, Urvashi speaks his name by mistake and is cursed to fall, the curse softened to last until the king sees their child. In a mountain forest she enters a grove closed to women and becomes a vine; the king, searching, finds the gem of reunion and she returns. Years later the hidden son Ayus is revealed, and a messenger from heaven allows her to stay for the king's lifetime.
What is different here:
No condition about being seen, no lambs, no lightning, no fire-sticks. New: the rescue, the queen, the stage curse, the vine, the gem, the hidden son, a happy ending on earth.
Indra, jealous of the king's life with Urvashi, tells the thunderbolt at his side to break their bond, and it does so by its craft. The king wanders distracted and sees her in a lake with five companions. He asks her to come back; she answers sadly that he cannot have her here and will have her again in heaven.
What is different here:
Indra and his bolt cause the parting, not the Gandharvas; five companions; the reunion is deferred to heaven.
Urvashi, under the curse of Mitra and Varuna, hears the king praised in Indra's court and comes to him, entrusting two lambs to him. Indra, missing her in his assembly, sends the Gandharvas, who take the lambs at midnight. After the yearly meetings the Gandharvas give the king a girl named Agnisthali, whom he leaves in the forest; returning he finds an ashvattha grown from a sami and kindles fire from it.
What is different here:
Indra orders the theft; the fire vessel is a girl called Agnisthali; six sons.
Urvashi tells Varuna that Mitra asked for her first, yet gives her heart to Varuna. Mitra in anger sends her to the world of men to be the wife of Pururavas, son of Budha. She bears Ayu and returns to Indra's world when the curse runs out.
What is different here:
Gives only the cause (Mitra's curse) and the outcome; no lambs, lake or fire.
A genealogy note: Pururavas, son of Ila, brought the three sacrificial fires and the nymph Urvashi from the Gandharva world, had six sons by her beginning with Ayus, and was destroyed by the curse of sages whose wealth he had seized.
What is different here:
No love story; he is a greedy king who is cursed; six sons.
Sources: The Satapatha-Brahmana, tr. Julius Eggeling (Sacred Books of the East 12, 41); Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer; The Vishnu Purana, tr. H. H. Wilson (1840); Kalidasa: Translations of Shakuntala and Other Works, Arthur W. Ryder (1912), section "Urvashi"; Vikramorvasiyam - Wikipedia; The Brhad-devata attributed to Saunaka, ed. and tr. A. A. Macdonell (Harvard Oriental Series 6); Srimad-Bhagavatam (Bhaktivedanta Vedabase); The Ramayana of Valmiki, tr. Hari Prasad Shastri (1952-59), Uttara Kanda