Ravana wants to kidnap Sita and so asks for Maricha's help, who then turns himself into a golden deer. The golden lusture of the deer lures Sita so much that she wishes to have the deer for herself. So she asks Rama to get it for her. Rama orders Lakshmana to take care of Sita while he goes for hunting the deer.
Rama succeeds in hunting down the deer after a long chase, but on its dying breath the deer shouts 'Sita Save me, Lakshamana Save me' mimicing Rama's voice. Sita falls prey to the trap and asks Lakshmana to go on a search for Rama. But Lakshmana says that no one can harm Rama. Sita, still very much worried, implores Lakshmana to go. Then follows the famous story of the Lakshman Rekha.