Season 1

A club cricket team is caught in crisis. It so happens that their star batsmen (Milind) is accused of drug trafficking and abuse, just before a crucial match and he is being hunted by the police. Convinced of his innocence and suspecting the rival team of foul play, the worried team members approach Detective Omkar Nath to find Milind and also solve the mystery. And the tale unfolds in a typical middle class Maharashtrian setting, where D.O.N discovers that Milind's mother and his Dadar Gymkhana coach are aware of his whereabouts. And in fact, they are hiding him in a Chawl. The prime suspects include the rival coach Tyagi, substitute Arun and local goon Sautya who had a tiff earlier, with Milind.

Kaniza Noor, with a hauntingly beautiful voice, seeks Detective Omkar Nath's help. Her past hides a secret that could ruin her marriage. An old lover, Anil Rai, reappears, demanding money for his silence, threatening her with old letters and photos. She wants the box with these items back. D.O.N has never seen her face, and as he investigates, he falls into a trap. He's accused of smuggling drugs, caught with cocaine in the box supposedly holding the letters. Anil Rai, a smuggler, was murdered by his lover Sapna and friend Raees. D.O.N realizes he can still trap Kaniza, unaware of his arrest. When he meets her, he encounters Julie and later learns both Sapna and Julie are the same. He also meets Anil's wife Kaveri and discovers Sapna was framing Kaveri to get revenge on Raees for cheating her.

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.

Imagine a kidnapper demanding ransom before the kidnapping, even giving a time and date for it. D.O.N faces a challenging case filled with twists involving an innocent 4-year-old, Gulla. His grandfather and parents receive a threatening call, making the intentions clear. It begins with Lala Radheyshyam Halwai from Bikaner, now a wealthy sweet manufacturer in Mumbai, who wants to return to Bikaner with his family. His grandson, Gulla, is his pride and joy. However, his son and daughter-in-law, born and raised in Mumbai, disagree. The family receives a note with Gulla's cut hair, demanding ransom or threatening to kidnap him. D.O.N is consulted, and the police are deployed, but the kidnapper still manages to abduct Gulla when Lala faints, and local ruffian Babban is captured with chloroform (a setup). Thomas, the driver, and Reshma, the nanny, are prime suspects as they have disappeared. D.O.N's investigation reveals a secret room in the mansion known only to three people.

Where there's a will... there is a dispute. Set in a typical Parsi Milieu, this story captures the drama and events that unfold after a millionaire dies under suspicious circumstances and leaves behind a fortune to just one single person, Jatin, an orphan whom he had adopted long ago and who has grown into a handsome young man who wants to study at Harvard! Detective Omkar Nath is called upon by chance... to solve the case by Jatin.