Past:
ACP Abraham Ozler is on vacation with his wife Anisha and daughter Jenny. He receives a call that requires him to investigate a double murder, and promptly leaves in his car. Mid-journey, he realizes that the call was faked and rushes back to find both Anisha and Jenny missing. Later Vineeth, a drug addict, admits to kidnapping both of them, hacking them to pieces and burying the pieces in a forest to take revenge on Ozler for arresting him in a
narcotics case. However, Vineeth claims that he had taken a large dosage of prescription drugs that night and consequently does not remember where the pieces were buried.
Present: Three years later, Ozler is chronically
depressed insomniac who experiences
hallucinations due to lack of sleep. He never received closure and remains distraught and miserable, as he cannot find his wife's and daughter's remains in spite of regularly visiting and questioning a now convicted Vineeth. He is also investigating a series of murders with his subordinates
SI Divya Sreedharan and Sijo T Venu. The killer leaves birthday cards at each murder scene, and the cards all have parts of the Latin quote, "Let conversation cease. Let laughter flee. This is where death rejoices to help the living". The killer is dubbed "The Birthday Killer" by the media. As the team unravels the connections, they discover Krishnadas, a man using an
artificial larynx, as a key suspect. They also learn that he was a prodigious singer as a teenager, and lost his voice due to a surgery mishap. Delving into the past, Ozler discovers a shared history among the victim's parents: Shivakumar and Selvaraj. They were postgraduate medical students at
Kozhikode Medical College in 1989. Shivakumar, Selvaraj, Xavi Punnoose (a retired police surgeon) and Alexander Joseph (now living in Dubai) were all found to have been friends and batchmates. They were recorded as having gotten into an accident, after which they parted ways. Meanwhile, Krishnadas breaks into Alexander's house and attempts to abduct him but is thwarted and arrested by Ozler. But even as Krishnadas is in custody, Xavi is kidnapped. Ozler then discovers that the Alexander in Dubai was a fake all along and that the real Alexander was still active and had abducted Xavi. The real Alexander attempts to kill Xavi in the same manner as the previous victims, but is arrested by Ozler and his men at the last minute. While in custody, he reveals his true motives.
1989: Alexander was a dedicated postgraduate student at the surgery department of
Kozhikode Medical College. Xavi, a fellow student of surgery, was inept compared to Alexander, and was consequently jealous as the professors favored the latter's skill. Shivakumar, a student of General Medicine, developed hatred towards Alexander for starting a relationship with first year
MBBS student Suja Jayadev, whom Shivakumar had been pursuing relentlessly. Selvaraj, a student of
Anesthesia and a drug addict, was expelled after Alexander caught him getting high and reported the latter to the faculty. During this time, Krishnadas was admitted to the Medical College due to a tumor in his throat, which affected his voice. Alexander was designated to assist in the surgery and he chooses Xavi to help him. During the surgery, Alexander was unexpectedly required to take the lead and he requested Xavi to cut the tie inside Krishnadas's neck. Xavi, fueled by jealousy and bitterness, cuts Krishnadas's
Vocal cords- which is why he lost his voice. Alexander reported Xavi's intentional act to the faculty, Xavi is blacklisted and both are suspended due to Alexander being the first assistant. Under the influence of drugs and alcohol, the enraged and bitter Selvaraj, Xavi and Shivakumar brutalized Alexander, putting him in a coma. Once sober, they fabricated an accident, faked injuries on themselves and told everyone that a drunk Alexander took them for a drive and crashed the car. Suja becomes depressed after this. One day, doctors suggested that Alexander's life support be removed and he be allowed to die peacefully. A heartbroken Suja lost all hope after overhearing this and committed suicide by jumping in front of a moving bus. In a fateful twist of irony, Alexander awakened on the 1st day of her death. After years of nursing care, he regained movement but loses most of his postgraduate memories due to
dissociative amnesia, including Suja, Xavi, Shivakumar and Selvaraj. 3 years ago, Alexander saw a TV program featuring Krishnadas, where some old videos of the latter singing are shown. This triggered his memories and Alexander slowly recollected his past. He learned about Suja's death and met up with a then wayward Krishnadas, and they planned the murders together.
Present: Xavi meets Alexander and Krishnadas in Ozler's custody and shows no remorse at all. Ozler regrets saving Xavi and tells him plainly that he deserved death. Astonishingly, Xavi dies on stage of
cardiac arrest at the release ceremony of his autobiography. Seconds before this happens, Ozler receives a call where the forensic surgeon Satheesh Madhavan reveals that Alexander had poisoned Xavi and all the victims with
methylene blue and
agar-agar, a lethal bacteria-infected
surgical ink before making cuts on their bodies. Later, it is shown that the truth gets revealed - Shivakumar is found dead in his car, while Selvaraj becomes drunk and his wife leaves him, realizing that he caused their son's murder. On his routine visit to Vineeth in prison, Ozler encounters Alexander and Krishnadas. Alexander cryptically utters "
Bone Residue", hinting at an unresolved truth about Ozler's family. Ozler realizes that if a bladed weapon is used to hack flesh, bone residue will always be present on the blade even after chemical washing. Ozler confronts Vineeth about this and the latter, unrepentant, challenges Ozler to dig deeper for the truth. == Cast ==