Vivaan Ahuja, a skilled MMA trainer, learns that his wife Anshika Maitra's heart can stop at any time and an operation is required. The operation is successful. As she recovers in the hospital, a terrorist group led by Saju Solanki attack the hospital to retrieve illegal arms dealer Ajay Pal Singh, the group's leader. Singh is responsible for the deaths of 18 Indian army soldiers due to his supply of faulty weapons to them, and was moved to the hospital for emergency surgery after his pacemaker was tampered with in prison. Patients of the hospital are taken hostage, including Anshika, while Singh is unconscious under anaesthesia after his surgery.
ACP Jayati Bhargav and her team are tasked to free the hostages. Vivaan, who is just leaving after visiting Anishka, is in the hospital basement, oblivious to the invasion until he is attacked by one of the terrorists. He manages to kill the terrorist. Shocked, he takes the black pouch belonging to the terrorist, which contains a walkie talkie and a remote detonator, and sneaks back into the hospital. He meets a hospital guard named Riyaz, and a child named Zubin who had been hiding, and befriends them. Jayati meanwhile is stunned to see that her daughter Aanya is being used by the terrorists, strapped to a bomb. Saju blackmails her, saying that he will blow up the hospital unless she supplies a helicopter and a bus to them. She agrees, but secretly plans to attack them. Vivaan learns the hospital's layout with Riyaz's help and plans to attack the CCTV room first so that Saju can't see him coming. He is attacked again but with Zubin's help, he kills the terrorist. The bodies of both terrorists are found and Saju orders Vivaan to be killed. Vivaan manages to contact Jayati intermittently and inform her about Saju. He continues to fight, kill, and evade the terrorists stationed around each floor and is finally able to take control of the CCTV room with Riyaz and Zubin. He then frees the patients held hostage on the ground floor. Saju, who is on the ninth floor, realizes that Vivaan is related to one of the hostages, and tries to figure out who it is. Unable to do so, he kills a nurse to force Vivaan out of hiding. Singh wakes up and they plan to escape.
Vivaan realizes during a conversation with Riyaz that Saju was lying to the police; he was never going to use the bus and helicopter he had demanded but rather escape through the sixth floor. He is actually planning to blow up the stairs and the elevator in order to erase evidence by killing the hostages. Vivaan relays this to Jayati, who decides to trust him and play by his information. She and her team enter the hospital, free Aanya, and deactivate the bomb. Vivaan kills Saju's accomplice and finally fights Saju. Saju is eventually killed after the falling elevator collapses on him, and Jayati shoots Singh to death. Jayati thanks Vivaan for his help, remarking that he should be given a medal for his work but respects his wish to keep his name and identity from the media.