Mohini Ekadashi falls in the bright half of Vaishakha, and it bears the name of the enchanting form Vishnu took at the churning of the ocean. Its katha, told by Vasishtha to Rama, is about Dhrishtabuddhi, a rich man's son who threw his life away and was turned around by a sage and this one fast.
The date of the next Mohini Ekadashi, with the parana window for breaking it in your city, is on the Ekadashi vrat dates page, which has a separate page for each Ekadashi. Below is the katha, retold in our own words.
The katha of Mohini Ekadashi
Yudhishthira asked Krishna which Ekadashi came in the bright half of Vaishakha. Krishna said, "The same question Rama once asked his guru. When he was parted from Sita and sorrow would not leave him, he asked Vasishtha for a fast that could lift grief and clear the mind. Vasishtha told him of Mohini, and of a young man who learned what it could do."
The merchant of Bhadravati
On the banks of the Saraswati stood the fine city of Bhadravati, ruled by a king named Dyutiman. In that city lived a merchant, Dhanapala, whose name meant "keeper of wealth" and who used his wealth well. He dug wells and ponds, planted gardens, built rest houses for travellers, and set up water stalls on the roads in summer. He was devoted to Vishnu and generous to everyone.
Dhanapala had five sons. The first four were steady and good. The youngest, Dhrishtabuddhi, was the opposite. He spent his days gambling and his nights in bad company, drank, lied, and treated his elders with contempt. He took money from the house without asking and lost it as fast as he took it.
His father warned him, then pleaded, then warned him again. At last, with a heavy heart, Dhanapala turned him out of the house. His brothers and relatives turned away too.
The years of wandering
At first Dhrishtabuddhi lived on what he had: he sold his rings, his fine clothes, his ornaments. When those were gone, so were the friends who had shared his pleasures. Hungry, he began to steal. He was caught, punished and thrown into prison, and when he was released the king banished him from the city.
He went into the forest. There he lived as a hunter, killing animals and birds to eat, always restless, always hungry, never at peace. The years went by like this, and his body and mind grew heavy with what he had done.
The drops of water
One day in the month of Vaishakha, worn out by grief and hunger, he wandered by chance to the ashram of the sage Kaundinya. The sage had just come back from bathing in the Ganga, and his clothes were still wet. As he passed, a few drops of water fell from the sage's garment onto Dhrishtabuddhi.
Something in him changed at that touch. For the first time in years, his mind was clear enough to see what he had made of his life. He fell at Kaundinya's feet and said, "I have done every wrong there is. I have nothing left, not even self-respect. Is there any way back for someone like me, a way that does not need money?"
Kaundinya looked at him with compassion. "There is," he said. "The bright Ekadashi of this very month is coming. It is called Mohini. Keep it with a true heart. It is said to clear faults piled as high as a mountain."
Dhrishtabuddhi did as the sage told him. He fasted, worshipped Vishnu, and kept the night awake, and he did it sincerely, with regret for the past and hope for what was left. The weight he had carried for so long fell from him. His life turned, and at its end, the story says, he rode on Garuda to Vishnu's abode.
Vasishtha told Rama that there was no fast in the three worlds like Mohini for lifting the fog from the mind, and that even reading this story brought the merit of a great gift.
Reading the story calmly
There is punishment in this story, prison and exile and a hard life in the forest, and the mahatmya speaks of mountains of sin. None of it is meant as a threat. The katha is really about the second chance: that a person nobody wanted to know could still be met with kindness, and that the way back began with a few drops of water and a sage who did not turn him away. Families tell it so that no one feels beyond return.
What the day is kept for
Mohini means the one who enchants. In the churning of the ocean, Vishnu as Mohini drew the asuras' attention away so the nectar reached the devas. The day is kept in the same spirit, for loosening the pull of habits and attachments that cloud the mind. The mahatmya says it removes delusion and grief and brings the merit of great pilgrimages and gifts; families hear those words as encouragement, not as a reckoning.
Because Rama is the listener in this katha, many families remember him as well as Krishna on Mohini Ekadashi.
How it is kept
Mohini Ekadashi falls in the heat of Vaishakha, so the day's charity often follows Dhanapala's example: water stalls, pots of drinking water, fruit and fans for those working outdoors. Many people bathe early, as Kaundinya had, and sprinkle a little Ganga jal before the puja. A fruit fast is common, and anyone who finds the heat hard should drink water freely. The rest of the fast follows the shared Ekadashi puja vidhi, from sankalp to parana.
The Ekadashis on either side
Before Mohini comes Varuthini Ekadashi, the story of King Mandhata, the bear and the fast at Mathura. After it comes Apara Ekadashi, in the dark half of Jyeshtha, about a murdered king and a sage's gift. To see the tithi on any day, use the panchang for your city.