Sanjay and Megha Dixit, a young couple, escape their homes and assume new identities in Mumbai, dreaming of a fresh start. They rent a sea-facing flat in Cuffe Parade at a low price from a smooth estate agent. However, their dreams shatter when Megha mysteriously disappears during a tonga ride. Sanjay, new to the city and with no one to turn to, seeks help from D.O.N.
The situation worsens when their flat is ransacked and the underworld demands 2 crores as ransom for Megha's release. D.O.N has only 12 hours to solve the case. Suspicion falls on various suspects, with crucial clues from a taxi driver and an observant tramp. It's revealed that Sanjay lied about his name; his real identity is Sanjay Srivastava from Gwalior.
D.O.N convinces Babban, the underworld killer, to give more time, revealing the real Dixits are still at large. The estate agent and his wife, posing as the secretary, opened a fake agency, renting the flat cheaply to mislead the underworld and buy time.