Chiriyakhana

Nishanath Sen, a retired judge and wealthy nursery owner, hires Byomkesh to locate Sunayana, an actress he believes is living under a false identity. He explains that Sunayana may be hiding inside his Golap Colony nursery and that uncovering her could also reveal hidden details about a long-forgotten film. Byomkesh accepts the case and is paid the advance to visit the nursery.

Byomkesh meets Bengali film expert Ramen Mullick, who fills in the backstory: Murari, the producer's son, was murdered while Sunayana was with him, and 20,000 rupees plus gold ornaments vanished. Sunayana was the prime suspect and had an arrest warrant, but she disappeared before she could be apprehended. Ramen promises to help Byomkesh with the investigation.

The next day, Byomkesh and Ajit visit Sen's bungalow and Golap Colony nursery, with Byomkesh in disguise as a Japanese horticulturist named Okakura and Ajit as his Indian assistant. Sen introduces the residents and allows Byomkesh to photograph everyone, building a visual dossier. The visit sets the stage for uncovering motives and identities among the colony's inhabitants.

Within a few days, Sen phones Byomkesh to arrange another meeting, but he is bludgeoned to death with a blunt instrument before they can meet. The murder shocks everyone and triggers a fresh police inquiry. Byomkesh and Ajit begin a more intensive interrogation of the nursery's residents.

A police inspector visits the colony and asks for Byomkesh's assistance in solving Sen's murder, unaware of their prior client relationship. Byomkesh agrees to help and starts re-interviewing suspects. The case becomes a complex web of motives and alibis.

Over the next few days, Byomkesh and Ajit question every resident and staff member, noting various motives and concealed histories. He records the interrogations with a voice recorder to preserve statements and contradictions. The investigation reveals that many people could have had reason to kill Sen.

Another murder occurs inside the Golap Colony: Panu, a deaf-mute witness, is killed in the same manner as Sen. The repetition of the method deepens the mystery and confirms a calculated killer is at work. Byomkesh doubles down on the investigative pressure.

Byomkesh discovers a tape recorded in Dr. Das's room that features him playing the sitar during the time of the murders, undermining his stated alibi. He realizes the recording was used as the background during Sen's murder, proving Das was not elsewhere. This is a crucial clue that begins to bend the investigation toward Dr. Das.

As the interrogation continues, Byomkesh examines an old photo of Sunayana and attempts to match it to several women among the suspects, discovering that Bijoy abandoned Mukul in favor of Banalakshmi. The motive hint points toward Bijoy and wealth, but it remains insufficient for a full conclusion. The search tightens.

A plastic flower found in Byomkesh's room triggers a new line of thinking and helps him re-evaluate appearances and disguises. He uses the clue to push for a more definitive identification of Sunayana among the suspects and to check for concealed relationships. The clue accelerates the unraveling of the truth.

Byomkesh correlates the evidence and discovers that Sunayana is actually Banalakshmi, a resident and employee of Sen's nursery, who has undergone plastic surgery to alter her face. He notes the jewellery and Sunayana's contracts stored by Dr. Das as further corroboration. This identification rewrites the suspect map.

Banalakshmi (Sunayana) finally confesses that Dr. Das exploited her beauty for money and that he orchestrated the murders of Murari, Sen, and Panu to destroy evidence. The couple's pattern of crime is laid bare, with Sunayana implicated in the cover-up while Dr. Das carried out the killings. The revelation closes the circle of deceit around Golap Colony.

The investigation ends with the realization that the serial killings were a calculated scheme tied to wealth and identity, exposing how appearances can be crafted to fool even close observers.