A troubled youth becomes a police informant in Kirumi. Kathir is a troubled youth, who regularly gambles in illegal bars and has run-ins with the corrupt police force. After being thrown in jail for the night, Kathir runs into family friend Prabhakar, who is a police informant and he arranges for Kathir to also become and informant. Even though he initially benefits from this new position, Kathir quickly becomes aware of the dangers that being an informant can bring.
Kirumi is a film that is part of a new wave of South Indian Tamil cinema. The film focuses on the world of police informants in India, who in some ways are the people who do the dirty work for the somewhat corrupt police system. The film also gives the message that the police and criminals are part of a larger system and, in many ways, they have a symbiotic relationship with each other.
There are many shifts in tone throughout Kirumi, with the film sometimes coming off as a comedy, while at other times the film is a gritty thriller. The film does become somewhat darker in the second half, as Kathir learns the downside of being a police informant, as he finds himself the target of assassins. The film does make an interesting commentary on the role of police and criminals in India, as well as a message that not every problems needs to be handled.