Raja Roychoudury or Kakababu (as he is better known), the crippled adventurous man and his nephew Santu and his friend Jojo become involved by chance in the case of ‘Ek Tukro Chand’. It seems as if a few pieces of stone or the ‘moon’ are being exhibited at museums all over the world. One such piece of stone has even been brought to Kolkata from U.S.A and is being exhibited at the Indian museum. It is stolen one day.
At the same time, Simon Boobumba, the brother of the Prime Minister of Burundi has been kidnapped after he comes to Kolkata.It seems as if both these cases have a link to each other.Kakababu meanwhile is approached by an old associate Narendra Verma, an CBI official who asks him to go to Ranchi and meet Thakur Singh, a feudal lord of that area who might have kidnapped Boobumba.After reaching there and meeting Thakur Singh, he and his gang have a few run ins with Thakur Singh and eventually at one point even the cops arrive, but find that a dummy Boobumba has been kept there.
Kakababu and his gang go to the hills where Kakababu receives a call from the gang who have stolen the stone and supposedly also have Boobumba with them. They ask him to get a huge amount of money or otherwise Boobumba will be killed.Kakababu meets them with a briefcase which contains money. They take him to another destination and discover that there is no money. They ask him not to play any tricks. He plays for time and soon the cops arrive there as well. Over there a Sardarji who is part of their gang is discovered by Santu to be none other than Boobumba and he is also the person behind the theft of the stone as it is discovered and is found on him.