Byomkesh and Ajit have been approached by Mr. Bagchi to investigate the whereabouts of arms which were left by the U.S. soldiers after the 2nd World War. They go to the Dooars, and get rocked by the murder of a young man, Amrito followed by the explosion of Sadananda Sur's house, killing him in the process. What follows are shocking truths of Sadananda, which is connected with the arms smuggling, ending in a suspense-filled chase with the villain.
