No, Kedarnath movie is not based on a completely real or true story. Kedarnath is a 2018 Indian Hindi-language romantic disaster film, written and directed by Abhishek Kapoor. Produced by RSVP Movies, Kedarnath stars Sushant Singh Rajput and debutant Sara Ali Khan in the lead roles.
Kedarnath is a fictional romantic drama with a real historical event as the backdrop. The movie’s core plot of an interfaith love affair between a Hindu girl and a Muslim boy is completely imaginary. There is no evidence of any real-life couple on whom the film is based. However, the movie uses the 2013 flash floods in the Himalayan state of Uttarakhand as its major setting and climax.

Plot Summary
The plot is set in the sacred temple town of Kedarnath in the state of Uttarakhand. Mansoor Khan is a porter who carries the pilgrims and their luggage up the arduous trek to the temple. Mandakini aka Mukku is the rebellious younger daughter of a Hindu Brahmin priest, Brijraj Mishra, who also owns a lodge and shops near the temple. Mukku is engaged to the nephew of the head priest, Kullu, but resents him.
Mukku hires Mansoor as her regular porter during her trips. During the course of their playful interactions, both fall in love with each other. Mukku’s family discovers the affair, leading to brutal violence against Mansoor. Mukku is forced into marriage with Kullu. She attempts to commit suicide but is saved. Mansoor vows to rescue her.
At this point, devastating flash floods strike Uttarakhand, with heavy rains and cloudbursts. Everything is destroyed in the temple town of Kedarnath. In the ensuing chaos, Mansoor risks everything to save Mukku and her family. In the climax, Mansoor sacrifices his life to ensure that Mukku and others are rescued by a helicopter.
Historical Backdrop
The central love story of the movie is created for cinematic drama. However, the disaster sequences are based on the 2013 flash floods in Uttarakhand, which is one of the worst natural disasters in India. The film incorporates real footage and events from this tragedy.
In June 2013, the state of Uttarakhand was hit by extreme rainfall, cloudbursts and a glacial lake outburst, leading to flash floods. There was massive destruction in the Kedarnath valley, leaving no structure standing except the shrine itself.