Jayanta Chowdhury, a ground engineer is gravely injured and is received by his fiancé, Kuntala who takes care of him. However Jayanta is not at peace as he had smelled conspiracy. He returns to Kolkata much to Kuntala’s dismay and starts following another ground engineer Sandeep Mukherjee, who he believes is playing up against his employer. Jayanta gets together with the Intelligence Officer Ranjit Mitra and traces Sandeep’s wherabouts. Sandeep is actually involved with the criminals Krishn Chand and Abdullah who force him to plant a bomb in an international aeroplane. Sandeep, rather unwillingly gives in as he needs money to treat his handicapped younger brother. Although he loves a girl named Ruby he is unable to marry her because of the same reason. Jayanta takes up the name of Arun Ray and befriends Sandeep to know about him. He soon realizes that Kuntala was Sandeep’s sister. In the meantime, Sandeep is made aware of Jayanta’s identity and his relationship with Kuntala and he decides to own up everything to him. However he is shot by the criminals but manages to own it up just before he dies. The criminals are caught and their conspiracy fails. Jayanta and Kuntala get together again.