This vrat has to be performed when an ashtami falls on the sukla paksha and it should be a Wednesday. The eight day of waxing
moon on a Wednesday.
On this day we have to pray to the Budha Graha for his blessings. This helps us to get rid of going to the hell.
Once there was a king called Nemi, the ruler of Mithila. He had wife named urmila. In a battle Nimi was killed and Urmila fled to Avanti kingdom along with her son and daughter. She joins a Brahmins family as a maid and daily she used to steals food grains for quenching the hunger of her children.
After few years Urmila dies and the son returns to Mithila and regains his rightful throne. His sister named Shamala gets married to the king of Avanthi called Dharamraj.
Shamala finds that they are seven rooms in the palace which are locked and asks Dharamraj, who tells her never to look into those rooms. As curiosity builds up shamala opens the doors only to find her mother tortured in the seven rooms in seven different methods.
She comes back very sadly to Dharamraj and asks him what was happening to her mother in those rooms.
Dharamraj says that it is for this reason only that I warned you not to enter the rooms and explains her that as her mother has stolen the food grains from a Brahmins house she was being given punishment for her stealing in the hell and that is what you have seen.
Shamala prays to Dharmaraja to help her save her mother.
Dharamaraja advices her to do the Budha Ashtami Vrat inorder to help her mother.
Shamala performs the same and her mother is released from the hell.