The story of ''Jagga Jasoos'' revolves around the infamous high-profile case of Purulia arms drop case, which took place in the year 1995 allegedly to overthrow the then Communist Government of West Bengal, India. Jagga (Ranbir Kapoor), a curious and shy young boy in a quaint little town lives a happy life with his accident-prone adoptive father, Bagchi (Saswata Chatterjee). Jagga, being self-conscious of his stammer, doesn't speak much; until one day Bagchi teaches him to "speak" in song. Some time later, after admitting Jagga into a boarding school, Bagchi suddenly disappears. Feeling abandoned, Jagga's only contact with Bagchi is a VHS tape that he receives in the mail every year on his birthday. Armed with sharp detective skills, Jagga sets out to solve the mystery of his missing parent. Along the way, he finds a partner in Shruti (Katrina Kaif), an accident-prone journalist with her own international criminal case to solve. Using a few tricks he learnt from Bagchi, Jagga, with Shruti, embarks on a mission to uncover details of his father's mysterious secret life and finds himself embroiled in a worldwide smuggling racket.