Aethiree movie tells Natarajan (Delhi Ganesh) who is a Brahmin house-owner near Triplicane temple looking for a right tenant for the upper portion of his house. He is naturally very protective of his college going beautiful daughter Gayathri (Kanika). Since he often fears that the prospective tenant might romance his daughter, he rejects all prospective tenants. He finally rents out the house to five bachelor students, who pretend to be good and later become a big headache for the father and daughter.
On the advice of 'Auto' (Vivek), Natarajan brings Subramani (Madhavan), who charades himself as 'Bottle Mani', a dreaded thug to vacate the student-tenants. Incidentally Mani, who stays with his Jailor uncle (Sundarrajan), was thrown out of his house as he refused to marry uncle's daughter. Taking advantage of the situation, Mani befriends the five boys and starts staying with them.
Priya (Sada) who is the daughter of a wealthy gangster (Fefsi Vijayan), engaged to an affluent sadist ACP (Rahman). On the day of her marriage, Priya comes to know that her fiancée is already married and had murdered his first wife in a sadistic manner but her father forces her to marry him to cover up his illegal activities. She consumes poison just before the wedding, but is mistakenly kidnapped by Mani and Auto.