'Tahaan' - is a fable-like journey of the eponymous eight-year-old boy, whose life revolves around the pursuit to find real purpose in his little world.
Tahaan (Purav Bhandara) lives with his grandfather (Victor Banerjee), his mother Haba (Sarika) and older sister Zoya (Sana Shaikh,) in the serene meadows of Kashmir. They all live in the hope that someday Tahaan's father, who's been missing for over three years, will return.
The death of his grandfather leads the local moneylender Lalaji and his manager Kuka (Rahul Khanna) to take away the assets of the family, including their pet donkey Birbal, against repayment of a pending loan. Now, life for Tahaan is his pastures. For Tahaan, bringing his favourite donkey Birbal back home becomes the sole purpose in life.
After various efforts at money-making, Tahaan approaches Lalaji with the prospect of regaining his lost asset but is devastated to learn that an old man Subhan Darr (Anupam Kher) has bought Birbal and taken him across the mountains... the same mountains from where Tahaan's father never returned.
But Tahaan sums up courage and chases after Subhan. The prophetic old man doesn't befriend Tahaan at first sight but slowly warms up to this energetic and determined soul whose love for Birbal is paramount. But at the end of the journey, Tahaan is further disheartened when Subhan gifts Birbal to his orphaned eight-year-old nephew, and even the long-time helper of Subhan called Zafar (Rahul Bose), cannot be of any assistance to poor Tahaan. On his way back home, Tahaan finally encounters a teenage lad ldrees, who convinces him that his efforts would never be sufficient to get Birbal back. Instead, he promises to get Birbal back for a favors. All Tahaan will have to do is carry a package across the mountains on his next journey. Seeing Tahaan's eagerness, ldrees hands him a grenade. He tells him that when the time is right he will be told what is to be done.
Tahaan sets off on his second journey with Subhan and Zafar, the grenade and package tucked away under Birbal's saddle. What is the price that Tahaan will have to pay for Birbal? And how far will he go to save his only meaning in life?
Tahaan is now at a crossroad where his ultimate decision would determine his fate... "Will he get Birbal back?"