Mahaan is an action-comedy drama. The movie follows the story of a famous lawyer named Amit (Amitabh Bachchan), who lives with his wife, who is pregnant. Their happy and peaceful life takes a turn when he is falsely accused of a murder. To protect himself, he runs away and gets separated from his wife. Later, his wife gives birth to the twins, Shankar & Guru (played Amitabh Bachchan) and alone brings them up. Many years later, the family reunites under the tragic situation. Will Amit finally be able to make things right and bring back his family together?