The Bargain
Urvashi, the most beautiful apsara of Indra's court, fell in love with King Pururavas of the lunar dynasty. She agreed to live with him — with two conditions: she would keep two pet rams, and he must never appear before her naked.
They lived together in joy for years.
The Trick
The gandharvas — divine musicians — wanted Urvashi back in Indra's court. They stole her pet rams one night, knowing Pururavas would be forced to chase them.
He ran after the thieves in the dark, forgetting everything. The gandharvas illuminated the room with lightning as he returned — undressed.
Both conditions broken. Urvashi vanished.
The Search
Pururavas was destroyed by grief. He searched everywhere — across the earth, through the celestial regions.
Eventually he found her at a sacred lake where she had come to disport with other apsaras in swan form. He pleaded with her.
She told him gently: she belonged to another realm. He had been her joy, but she was not of his world. He should return.
She told him he would be granted one night with her — their son would be born — and after that she might return for a time more.
The Teaching
The Bhagavata Purana uses this story to illustrate the nature of attachment to things that are inherently transient — apsaras, celestial pleasures, any love that belongs to a different order of existence.