অদৃশ্য ত্রিকোণ

Following the postponing of his departure, Mohan Babu seeks the help of Byomkesh and Ajit in solving Reva Sarkar's murder case. Suspecting Sunil, Reva's husband and alcohol addict, Mohan Babu asks Byomkesh Bakshi to help him collect evidence.Unable to conclude anything from Mohan Babu's story, Byomkesh decides to nab the culprit in Sunil Sarkar with the help of deceit. He asks Mohan Babu to bring him a copy of Reva's handwriting, a tape recorder and asks Sunil Sarkar to visit him.