'Paasakkara Pasanga' happens to be Thozha's tag line. The film's story rightly proves it. Based on friendship, Thozha demonstrates the basis for true friends and friendship.

Raja (Nitin Sathya), Arivazhagan (Prem G. Amaren) and Ghajini (Vijay Vasanth) are friends. They share a room in a bachelor's mansion. Raja, an engineer, works in a company. Ghajini is an amateur performer in movies and Arivazhagan is a graduate in search of a good job. Raja is very kind-hearted and caring by nature. A Good Samaritan, unassuming and generous, he is forthcoming to help even strangers. Raja is the only earning member in the group and he is the one who fulfils the needs and wishes of the other two members in the group.

Meanwhile, a fourth member joins this gang. Velu (Ajayraj) comes to the city from his village by bus. During the journey, he leaves his baggage with his co-passenger Arivazhagan. Unfortunately, Velu forgets the baggage and gets down at his stop. Realising his absent-mindedness, he comes back to claim it. But in the meantime, desperate Arivazhagan had spent Rs. 20,000 from Velu's cash. Raja hears about it, and unable to find a fitting solution to the problem, offers Velu a space in their room. Happy with the arrangement, Velu moves in. Despite the initial friction, the four young men become a close-knit group.

However, nobody had probed the real reason behind Velu's migration as well as his mission. In fact, Velu is determined to find his dead sister's lover, the man on account of whom she had ended her life. He is also determined to kill the selfish coward, the indecisive weak-willed rogue, when he finds him. Though it is mutually beneficial that the harrowing tale had not been discussed among the roommates, the tale must surface. When the true reason for Velu's arrival is revealed, it is going to be a most unpleasant experience for a particular member of the gang. Who is the criminal? When his mask is ripped off, will he still be able to remain in the gang? What made him love and subsequently spurn the poor girl who paid with her life? Watch Thozha and get the answers!

Nitin Sathya, Prem G. Amaren and Vijay's performances are very natural. The young guys' looks, demeanour, and their easy and friendly chatter establish proximity and an easy connection with the audiences. Director Sunderaswaran, who has worked with eminent directors such as K. Balachandar, Sundar K. Vijayan and Yar Kannan, is the man behind Thozha. He has made Thozha as an all-round entertainer with every scene making an impact.