[1] It stars Cheran and debutant Dipa Shah alongside an ensemble cast including Y. G. Mahendra, Lakshmi Ramakrishnan, Jayaprakash, and Selva in supporting roles.
The scene then shifts to a New Year's celebration by the beach, where a cardboard box atop a parked car attracts the attention of revellers.
Amputated male arms are found in the boxes, and the case is put onto Senior Inspector J. Krishnan, known as J.K. (Cheran), of the CB-CID.
He is a brooding ex-cop who shifted to the CB-CID from law and enforcement and at present is searching for his sister Charu (Ineya), who disappeared six months prior.
Prakash (Shankar) and Tamilselvi (Dipa Shah) are two junior officers who are put onto the case to assist J.K.. At the morgue, they meet Judas Iscariot (Jayaprakash), a medical examiner, to investigate the hands.
Purushothaman had been accused of bribery, and his wife Annapoorni (Lakshmy Ramakrishnan), a professor at a women's college, of instigating a 19-year-old lab attendant named Manikandan to have sex with her.
We then find that ACP Thirisangu (Selva), Isakki Muthu, Duraipandi, Sharif, Inba (Yugendran), Raghu's murderer, and the missing men – Nagu, Moorthy, and Rajamanickam - are in cahoots.
A new box with the autorickshaw driver's severed arms appears in a club used by two of the named men, and Sharif's head is found outside Isakki Muthu's police station, minus its eyelids.
J.K. triangulates all misdeeds to ACP Thirisangu and Isakki Muthu, as all the severed body parts were found in areas under the ACP's jurisdiction (notwithstanding the fact that the Purushothaman family's cases were handled and closed by Isakki Muthu himself), but his boss Chandramouli (Aadukalam Naren) refuses to have the officers questioned, fearing higher pressure.
He leads them to a van wherein they are gassed and knocked out, but as they are leaving, a shootout takes place between Thirisangu, J.K., and their comrades, in which Judas dies after confessing.
Thirisangu & Co. are revealed to be running a racket which involves kidnapping and drugging virgin girls, who are then stripped naked and raped before Duraipandi and his friends (all wealthy men in their late 50s and early 60s who are impotent), in return for a huge sum of money.
Suja (Srushti Dange) is one such victim (the girl in the auto), apparently having been abducted as revenge for what Duraipandi perceived as public humiliation at the hands of her family.
Nishanth is caught by Isakki Muthu but is distracted by the arrival of Duraipandi & Co. (all of whom have had their eyes gouged out), and also Britto and Manikandan, both with their tongues cut off.
Isakki Muthu manages to wound Purushothaman with one bullet and tries to finish him off, but before he can do so, Annapoorni rushes out and stabs him in the head, killing him instantly.
After participating in a photoshoot and a few early test shoots, Stalin opted out and cited he wanted his first film to be a comedy rather than a thriller.
[5] The Times of India gave 4 stars out of 5 and wrote, "With its apt casting and superb performances and direction, Yuddham Sei carries all the weapons needed for it to win its battle at the box-office".
[8] The Hindu wrote, "Mysskin is a thinking director, who makes no bones about his yen for makers in the league of Kurosawa and Kitano.
[9] IANS gave 3 stars out of 5 and wrote, "Despite slow second-half, the films does impress as a smart and realistic detective story".
[11] Deccan Herald wrote, "Stylised camerawork, haunting score and decent performances keep one interested, though the film is pulled down by its own weighty expectations.