Hero Rishi Ritwik, Yogi Babu and two others have been living together for years now. Since they have no families of their own, they lead their lives in North Chennai's dump-yards. At the same time, the councilor in their area gives them small jobs occasionally and comes to their rescue each time they end up in a mess. Heroine Archana Ravi, who is saved by Rishi from a major problem during her school days falls in love with him. Although Rishi rejects her advances, he accepts her love after his friends compel him.
In the meantime, a group involved in illegal drug trade are evading the police when they throw away their drugs in the dump-yard which Rishi ends up confiscating. Upon realizing that the drugs are in Rishi's possession, the group decides to kill him. When their attack results in a failure, the group tries to get the job done by paying off the area councilor. Rishi comes to know the plan the councilor has hatched to get him murdered. However, with the help of his friends, he kills the councilor before he could lay his hands on him for his betrayal. The police come in to arrest them, but Rishi and his friends decide to keep a low profile by going into hiding with help from a North Chennai don. In the meantime, one of the four friends falls in love with the don's daughter and elopes. This angers the don and what action he resorts to next, what happens to the four of them, the fate of Archana forms the rest of the plot of Attu.
Rishi, who plays the titular character Attu has lived in the role of a North Chennai youth and has pulled it off in terms of speech, mannerisms and expressions. In addition, he has handled the film's romantic portions with ease and has taken efforts to blend into the North Chennai background. Although Archana Ravi's role is small, she satisfies viewers with her act; especially in the scenes she's paired with Rishi. Yogi Babu and his friends have delivered terrific performances and make the film entertaining on many occasions. Especially in scenes when Yogi Babu says he too is a rowdy, it is a delight to audiences. We also get to know what goes on behind the lives of councilors and dons in North Chennai in the film.
Director Rathan Lingam needs to be complimented for his efforts to make a film with a North Chennai backdrop. His casting choices are on point with the film's screenplay requirements. Viewers, who are generally used to watching Central and South Chennai in films up until now have been introduced to the Northern part of the city which is a new experience for them. The filmmaker has painted on screen the lives of people living in the region showing us how fights and panchayats happen, crimes are committed and so on. Bobo Shasi's background score as well as songs are good; especially the one sung by veteran singer L. R. Easwari. Cinematographer Ramalingam has done a commendable job with his camera skills and shot the film well.
In short, Attu is one-time watchable.