Undekhi

Five years after Season 3, Rinku rebuilds his Chandigarh empire with his biological father Mahinder Atwal, expanding globally through a high-stakes deal with the Dhillon brothers, led by hip-hop star Bobby Dhillon. As Papaji awaits a crucial court verdict from prison, Ghosh joins Rashi in probing a chilling string of missing girls. When Papaji is acquitted and walks free, Rinku vows to destroy him. A war between father figures becomes inevitable.

As Rinku prepares for Bobby Dhillon's high-profile music launch, Papaji secretly moves against Mahi. Ghosh's probe into missing girls leads him to the same event, bringing him face-to-face with Rinku. Papaji abducts Deepika to locate Kavita, a witness to Muskaan's death. When Mahi learns Kavita is alive, he kills Deepika and leaks Kavita's location to Papaji. Daman reaches Kavita first and learns a fourth person was present the night Muskaan died-before DJ kills Kavita and shoots Daman, leaving his life hanging by a thread.

Rinku and Papaji's war escalates when Papaji, secretly backed by Narcotics, orchestrates Bobby Dhillon's assassination, shattering Mahi's drug empire. Jogi turns on Rinku, forcing him to ally with Sukhi to save the deal. Daman tells Rinku that a fourth person was present the night Muskaan died, suggesting Papaji may have been framed. As Saloni investigates, Papaji strikes again, tipping off Narcotics and seizing Rinku's entire consignment, reclaiming the upper hand.

Ghosh traces the missing students to Vikram Saluja's Dreamroots Foundation, raising suspicions of Rinku's possible links to trafficking. Rinku learns Sukhi betrayed him by siding with Papaji and Narcotics; in response, Jogi kills his own brother but remains loyal. Seeking safer distribution, Rinku and Mahi turn to Vikram's logistics empire, only to face a rival offer from Papaji and Daman. As Vikram plays both sides, Rinku exposes Papaji's covert deal with Narcotics, triggering a public scandal and shifting the power balance once again.

With Papaji under scrutiny, Vikram backs Rinku and revives his deal with Jogi Dhillon. A desperate Papaji turns to Kanwal's brother Harmeet, who reveals buried truths and hands over Kanwal's letters. Ghosh uncovers the "Royal Circle," a powerful syndicate tied to the missing girls, and begins suspecting Vikram and Rinku, while questioning Teji's death. As Daman aids Ghosh, shocks emerge - Papaji learns DJ is Mahi's illegitimate son, and Saloni discovers DJ was Muskaan's killer.

Papaji confronts DJ about being Mahi's illegitimate son and offers him the Atwal legacy. Daman uncovers a clue on Natasha's phone pointing to a secret Royal Circle meeting, while Rinku grows suspicious of Vikram. Saloni blackmails Mahi with the truth about DJ killing Muskaan. DJ seemingly betrays Mahi by leaking a drug consignment to Papaji, triggering a narcotics raid - but it's a trap. Gunfire erupts, Lucky dies saving Papaji, and as DJ escapes, Papaji reveals the truth to Rinku: DJ is Mahi's son.

Mahi claims DJ as his son but orders him to stay hidden as Rinku goes to war after Lucky's death. Mahi lies to Rinku, saying DJ has gone rogue. Ghosh and Daman uncover Teji's murder and force Natasha to reveal the Royal Circle's secret auction at Vikram's hotel. During an undercover raid, Daman and Natasha kill Vikram but Daman is badly wounded. As DJ ambushes Saloni, Rinku intervenes and finally realizes the truth-Mahi orchestrated Muskaan's murder.

Rinku kills DJ, avenging Muskaan and uncovering the truth-Mahi murdered Kanwal, orchestrated Muskaan's death, and helped build the Royal Circle. Rinku and Papaji finally reunite as father and son. During a Royal Circle bust, Natasha gives Ghosh a hard drive exposing powerful clients. Mahi retaliates by kidnapping Samaira, forcing a final showdown. Rinku, Papaji, and Ghosh defeat Mahi and rescue Samaira-but an unknown man arrives, demanding the drive and warning that this war is far from over.