Milon Tithi revolves around a male and two female characters: Arjun, Ahona and Bonhi. Arjun is a rich, young man that had a strong infatuation for Bonhi, yet he marries Ahona. Ahona is the daughter of a house owner and Bonhi is the daughter of a maid servant. Arjun always kept Bonhi happy, even with all her greedy needs. Ahona sees Bonhi as her best friend, but Bonhi dislikes Ahona and uses Arjun and separates him from Ahona. The story ends with Arjun and Ahona's separation.
Three year leap
After three years everyone thinks Ahona is dead and that Bonhi killed Ahona's parents. Ahona vows revenge on Bonhi. Ahona has a son named Chiku, but he's actually Bonhi's son. A new man enters Ahona's life named Aditya. Aditya loves Ahona a lot, yet Arjun still loves Ahona. He draws Ahona a painting every day. Bonhi has now become the owner of Mallick's villa. She is making the Mallick villa a living hell. Ahona A.K.A. Meera buys the Mallick villa and returns the property papers to her father. Later, Bonhi and Mrinal get arrested and Bonhi and Mrinal confess all their crimes. Bonhi gets out of jail but Mrinal is sentenced to jail for seven years.
Three month leap
After a few days, Ahona and Aditya marry and Bonhi's father appears. Ahona reunited Bonhi's father and mother. Later after many twists Bohni and Arjun get married forcely by Ahona. There was a big conspiracy against Ahona and Aditya. The conspiracy is plotted by none other than Arjun. Later Arjun kidnaps Aditya on the day of his and Ahona's weeding but Bonhi gets to know that Arjun is the one who kidnapped Aditya. Later Ahona rescues Aditya from Arjun. Then Bonhi tells Ahona Arjun is behind all the kidnapping and everything else. Then Ahona Aditya, and Arjun Bonhi goes for honeymoon. There is a big conspiracy to kill Aditya plotted by Arjun. Ahona saves Aditya many times from Arjun. Later she gets to know everything is being plotted by Arjun. Later Bonhi in Ahona's avatar pushes Arjun from a cliff. But Arjun thinks it was Bonhi. She took Ahona's avatar so the whole blame can get on Ahona.
One year leap
Later Ahona aka Bonhi pushes Arjun over a cliff. But everyone thinks Ahona was the one who pushed Arjun from the cliff. Leaving everyone to think that Arjun had died one year ago. One year later, Chiku is four years old. Arjun comes back and pretends to be Jishnu who got lost many years ago by falling from a cliff. Arjun goes to Malick's house to take revenge on Ahona as Jishnu. Will Ahona ever discover Jishnu is none other than Arjun? Later it will be revealed that it was not Ahona who pushed Arjun from a cliff actually it was Bonhi. She was the one who pushed Arjun from the cliff, in order to obtain all the property of Arjun. Later she joins hands with Jishnu aka Arjun to ruin Aditya and Ahona's life. Will she kill both Ahona and Aditya? Or will Jishnu aka Arjun ever find out the true colors of Bonni? Later Mrinal comes back to seek revenge from Ahona. Bonhi calls Ahona and fakes that Rahul has kidnapped her and tells Ahona to come to a temple to rescue her. It turns out to be a fake kidnapping to trap Ahona in their evil plans. They will try to kill Ahona. Will Ahona die or Bonhi's true colors be revealed? Bonhi's true colors are revealed in front of everyone and she and Arjun are jailed for some months.
Six months later
Everything is normal in the Mallick house. Bonhi writes a letter to Ahona that she will never come back in her life to trouble her. The show ends on a happy note on Chiku's sixth birthday.
