Dr. Somshankar Roy, a social scientist, engages Swagato and Anwesha to create 'mock' crisis on the streets. The aim was to observe reactions of people to different forms of crisis happening around them, and to analyse and derive conclusions about human behaviour from them. But all theories and deductions go astray when they come face to face with a real crisis in their own lives and cannot decipher whether the crisis is MOCK or REAL.

Pupul is twelve years old. But, instead of studying and playing like other twelve year old, the only thing that interests him is solving cases. His two friends, Tatai and Bhebli, are equally enthusiastic on being sleuths and assisting Pupul. Pupul calls himself Captain Spark , roams around with a toy pistol and dreams of possessing a durbin (binocular), which, according to him, will make him a real detective. So when his uncle presents him one on his birthday, disaster strikes. Looking through the durbin, Pupul witnesses a murder and decides to catch the culprit.