Help with some information needed

You may remember the episode in which the famous Bengali Horror film director's spirit enters Tiwari's body when he sits on his chair (antique chair brought by Saxena where Bengali director used to sit) and Tiwari behaves very weird , beats people up and calls Angoori sister. A Bengali actor called Arindam was Bibhuti's look alike who was in mutual love with the director's wife Mishti.

When Bibhu, Angoori and Anita go to Kolkatta to meet Mishti, she is gardening and singing a very, very beautiful Bengali song.

Can anyone tell me what is that song and from which Bengai movie, I loved the song and would like to get it . But first i need to know which song it is. 

Thanks.