A devotee of Bhagwan Shri Hanuman, Arjun Singh Rathod is in love with Lisa, a Christian, who was sired by an Indian mother and Caucasian father, runs into problems with his father, who wants him to marry a Hindu. He decides to break all ties with his family, both turn atheist, get married, and re-locate to live in 1920s Bombay. The duo then re-locate to renovate a mansion in Palanpur. Shortly after their arrival Lisa suspects that there is something odd about a particular room in the mansion but Arjun dismisses this. He will soon regret this, as well of forsaking their respective religions, after he finds Lisa possessed by what appears to be a demonic and seemingly invincible male entity.

In the year 1920 at Palampur, India, an architect arrives at a large manor house. The manager of the mansion, MK, discusses how its owner wishes to have it torn down with a hotel constructed in its place. Later that night, the architect is killed by a mysterious force. It turns out the first architect who had come before him was also killed in a similar manner some time ago.
Now the third architect who is brought in, Arjun Singh, is a religious, true devotee of lord Hanumaan and devoted to his family; but he is also in love with Lisa. This meets strong disapproval from his family because Lisa (born of a British father and an Indian mother) is of mixed faith. Arjun decides to marry Lisa anyway. As he travels to Mumbai, his father and his brothers intercept his car, beat him up, and try to burn Lisa alive. Arjun fights back and decides to disavow his faith and his family for Lisa. He ultimately becomes an atheist.

Karan (Shahid Kapoor) is a shy and nerdy canteen boy and college student, running a café with his friend Murugan (Johnny Lever), and Tanya (Rimi Sen) is a student in the same college. She is the most popular girl on campus. Karan is in love with Tanya but is too shy to tell her. After he musters some courage and rescues her step-brother from some goons, he catches her attention and is eventually able to invite her to a fake birthday party. On her way there, Tanya witnesses the murder of a scientist, Khurana (Om Puri) by his evil twin brother, the underworld don Mehboob, and as a result is forced to flee the country to save her own life, since the law had been bought out by the very same killers. The scientist had stored a secret code in a stuffed toy, a parrot, now being sought by Mehboob, and Khurana was able to hide the toy in Tanya’s car before being killed. Unawares, Tanya leaves the toy at home before fleeing the country, and the toy is later picked up by Karan, ignorant of Tanya’s fate.