Gongotri is an Action Romance based movie. In which, Neelakanta Naidu (Prakash Raj) is a big factionist. He has a loyal confidant called Narasimha (Suman), who is willing to give his life for the sake of his master. After gap of many years, Neelakanta Naidu's wife gives a birth to a baby daughter. But all the earlier babies born to Neelakanta Naidu expired due to some unknown reason.
The priests advise Neelakanta to name his daughter as 'Gangotri' (Aditi Agarwal). They also warn Neelakanta that the kid is having 'jalagandam', hence they ask Neelakanta to take Gangotri to the holy place of Gangotri in Himalayas and do the 'abhyangana snanam' (bath with turmeric, milk etc.) for the next 15 years. After 15 years, Gangotri would be free of any dangers.
When nobody could entertain the kid Gangotri; Simhadri (Allu Arjun) - the son of Narasimha - makes her smile by entertaining her with a song. Simhadri becomes a servant cum friend to Gangotri. They grow together. In the mean time mother of Simhadri (Seeta) sacrifices her life to save Neelakantam.
When Gangotri attains puberty, Gangotri's aunt (Sakuntala) restricts Simhadri from meeting Gangotri. Gangotri and Simhadri realize that they fell in love. When Simhadri comes to Gangotri's place clandestinely to meet her, they are caught red-handed by Neelakantam. Neelakantam beats Simhadri. Meantime, Narasimha comes to the spot and interferes. This causes a rift between Neelakantam and his trusted lieutenant Narasimha. Neelakantam is misinformed about Narasimha's intentions; hence he bombs the house of Narasimha. Simhadri is away at that time. When Simhadri comes to know that Neelakantam is responsible for the bombing, he comes to Neelakantam's house and challenges that he would marry Gangotri in 365 days.
Rest of the story how Simhadri married Gangotri.