Aham is the story of Sidharthan (Mohanlal), who grew up in a disciplined and strict environment and tries to lead his family life along similar lines. But his wife (Urvasi (actress)) is not able to adjust with his crazy lifestyle. She wants to become self-reliant but this creates suspicion in Siddharthan's mind. In a resulting argument and physical struggle, she gets pushed from the balcony and goes into a coma. This makes Siddharthan lose his mental balance. Later he ends up in a mental asylum and leads a spiritual life there.