Poornima from chennai receives a marriage proposal from her boyfriend Siddharth from kovai , while she was about to pick her friend Dharshana. During dinner, Darshana reveals that her six-month-old (11 years) love marriage is falling apart, and she's planning to get a divorce. This revelation triggers Poornima's fear of commitment, prompts her for a breakup.

Siddharth, upon receiving a breakup message, travels to Chennai to meet Poornima's dad. Despite impressing him, the final decision rests with Poornima. After an honest dinner conversation, they agree to try a week-long live in relationship with three strict conditions from her side. Siddharth reluctantly agrees.

Siddharth and Poornima overcome the hurdle of convincing a suspicious guard and their first fight arises when Poornima discovers Siddarth's lack of cooking and cleaning skills. Poornima installs a lie-detecting robot, JUNO, which Siddharth dislikes. The day ends in chaos as someone jumps from their building.

The next morning, Siddharth accidentally tosses an empty condom box in from the balcony which grabs the attention of suspicious Association Secretary and one more flat mate. Meanwhile a surprise visit of Darshana's arrival angers Siddharth, who leaves the house which make the house left with only two girls alone ending up confronting the suspicious secetary. Poornima cleverly deals with their moral policing, almost getting caught.

Siddharth learns about his family's plan for his engagement to Anu, who is the sister of his brother's wife and shares it with Poornima. They face a threatening meeting with the association who accuses them for using the apartment for fun, but manage to escape by threatening a defamation case. That night, Poornima expresses her feelings of disharmony in their relationship to Siddharth.

Siddharth decorates the apartment, impressing Poornima to bring harmony. Saarangan visits unexpectedly, and the police arrive to add more confusion, but Siddharth handles it with Juno's help. Siddharth and Saarangan bond over drinks, and Poornima finds the harmony she sought.

Siddharth and Poornima's takes a sweet revenge on the association people which goes wrong, resulting in the flat President's hospitalization. They have a fight that connects their previous arguments and break up due to Juno's untimely interruption. Poornima leaves the next day, with two days left in their stay in that house.

Siddharth reunites Poornima's family and leaves with a hard goodbye. Later, Poornima invites him for coffee and offers to restart their relationship in Australia. But....