Aditya's relationship with Devyani Bhowmick, a doctor who is being investigated for malpractice.Aditya is attempting to pass a health bill that is opposed by the pharmaceutical lobby.Prithvi Singhania's affair with Antara Mane Shinde, the wife of Aditya's coalition partner.Naina Singhania attempts to get back into Aditya's inner circle.Shankar, as well as kidnapping the son of the prison warden. Jai Singh Rathod's plan to break Roshan out of prison, involving killing a mob boss and delivering his head to B.E.S.T.Veer Singh Rathod works to stop the outbreak at the Hotel Gateway Residency from spreading, including tracking down a guest who escapes.The cure is circulated to treat everyone infected, but a video of Jai killing Shibani is released onto the internet and Shibani's mother Nupur takes revenge by shooting him. He initially identifies Devyani Bhowmick as the culprit, but she was framed by her father Bhisham, who is arrested by Jai. Jai tracks down the last vials and attempts to uncover the true mastermind, who has developed a cure for the virus. Meanwhile, Bhisham Bhowmick is exposed to the virus and it spreads throughout the city, infecting Aditya Singhania. Siddharth agrees to trade Vaidehi for his son, but at the exchange the ATU intervene and Roshan is killed by Jai. However, as the ATU are closing in Roshan coerces Siddharth Saigal into helping him by taking his son hostage. Roshan's daughter Vaidehi Sharma is located, and Kiran Rathod goes undercover as her to lead the ATU to Roshan. Through Haroon's girlfriend Maya they track down one of Roshan's old girlfriends, but Roshan orders the execution of Shibani Mallick which Jai is forced to carry out. However, a vial of virus is released at the Hotel Gateway Residency, where Veer Singh Rathod and Gyan Thakkar attempt to control the outbreak. The ATU interrogate Dhruv Awasthi and trace a middle man to a club, where they arrest Balraj, one of Roshan's men. He vows to get revenge on Jai and the Indian government by releasing the virus in Mumbai. During the virus exchange, the ATU intervene and Haroon is killed, but Roshan escapes with the 6 vials of virus. They go to collect the virus but Roshan almost scuppers the deal by bumping up their price, but Dhruv agrees to the new terms.
Jai and Haroon bring Roshan up to speed on their deal whereby a an arms dealer is going to pay them to release a weaponised virus in 6 major cities. Jai successfully breaks Roshan out of prison and delivers him to Haroon, and Shibani, Vedant and Gyan Thakkar reveal to Prime Minister Aditya Singhania that they have been planning a sting operation to get Jai undercover with the Sherchans. When a deadly virus is threatened to be released by Roshan's brother Haroon, the ATU including Shibani Mallick and Vedant Acharya work to track down Kush Sawant, the carrier of the virus. Roshan is scheduled to be executed that day, but Jai enacts a secret plan to break him out of jail. Three years after Day 1, Jai Singh Rathod is struggling with alcoholism after the loss of his wife and his efforts to put renowned terrorist Roshan Sherchan in prison.