Director: Anubhav Sinha
Shekhar Subramanium, a game designer, has delivered a number of commercial failures; his boss gives him one last chance to develop a successful game. To impress his skeptical son Prateek, Shekhar uses his son’s idea that the antagonist should be more powerful than the protagonist. Jenny, his colleague, uses Shekhar’s face as a model for that of the game’s protagonist G.One (short for Good One), while the shape-shifting antagonist Ra.One (short for Random Access Version One and in Hindi Ravan) is made faceless. The game contains three levels, the final level being the only one in which either character can be killed. Each character possesses a special device – the H.A.R.T (Hertz Amplifying Resonance Transmitter), which gives them their powers. Upon reaching the last level, the characters get a gun with one bullet; the opponent can be killed by this bullet but only if his H.A.R.T is attached.
Aakaashi, another colleague, notices unusual glitches but ignores them. When the game is officially launched, it receives a standing ovation from the audience; Prateek insists on playing it immediately. He logs in under the ID Lucifer and proceeds to the second level, but is interrupted. Ra.One, angry that a player has proceeded so far, determines that Lucifer must die. He uses the wireless technology to enter the real world. Aakaashi informs Shekhar, who rushes home, fearing for his son’s life. Aakaashi is murdered by Ra.One, who then takes his appearance and hunts down Lucifer. He meets Shekhar in the process. In an attempt to save his son, Shekhar claims that he is Lucifer, but his lie is exposed when Ra.One scans his identity. He kills Shekhar and makes it look like a car accident.
Sonia, Shekhar’s wife, is devastated after his death and decides to return to India. Prateek realises that Ra.One has come to life and was responsible for his father’s death. He informs Jenny and she tries to bring G.One into the real world. Meanwhile, Ra.One kills Aakaashi’s mom at her house on his killing spree while in guise of her son Aakaashi. Having murdered the old lady in his vengeance-driven carnage, Ra.One chases Prateek and Sonia on their way in a wild car chase on their way to the airport, but G.One appears, having entered the real world, and causes a gas explosion which temporarily disables Ra.One. G.One takes Ra.One’s H.A.R.T. and accompanies the family to Mumbai after Sonia realises that he can protect her son.
Ra.One returns to life, takes the form of a model (Arjun Rampal), and tracks down G.One. Hypnotising Sonia, he assumes her form to kidnap Prateek. Ra.One then instructs G.One to give him his H.A.R.T. back, and sends the real Sonia in a malfunctioning local train. The train crashes but G.One saves Sonia and the others in time. To save Prateek, he fights Ra.One; both reach the third level. G.One tricks Ra.One into shooting him without his H.A.R.T. attached. Furious, Ra. One creates ten copies of himself. Prateek, unable to identify the real Ra.One, remembers something his father had said to him: “If you join the forces of evil, its shadows shall always follow you”. The duo realise that only one of the ten Ra.Ones has a shadow: the original one. G.One shoots and destroys him with the sole bullet and returns to the virtual world.
Six months later, Prateek and Sonia return to London, where Prateek manages to restore G.One to the real world in remembrance of his late father.