On a bright morning in Chennai, V. Saravanan receives a wedding invitation from his ex-girlfriend, Meera Hansika Motwani, along with a note asking him not to attend. Undeterred, Saravanan Udhayanidhi Stalin and his friend Parthasarathy Santhanam drive to Puducherry to stop the wedding, replaying memories of their shared past on the road.
Throughout the journey, Saravanan recalls the history that shaped him: he comes from a dysfunctional family. His father Varadharajan N. Azhagamperumal, a college professor, stopped speaking to his wife Shenbagam Saranya Ponvannan the day after their wedding, while Shenbagam now studies to earn a degree and win back his affection.
Inside this tangle, Meera, a trainee air hostess, captures his heart after a chance sighting in traffic. She warns him through her father, DCP Mahendrakumar, of the uphill path to her love. Meera challenges Saravanan to transform himself—shaving, dressing well, dropping Partha, and becoming punctual—if he hopes to win her. He answers the test by prioritizing Meera over Partha, straining their friendship but inching toward change.
With effort and a bit of luck, Saravanan helps Partha reunite with his own lost love, and the two chase Meera to Mumbai, where Meera finally admits that she loves Saravanan. Parallel to this, Varadharajan begins to reconcile with Shenbagam after Saravanan confronts him, softening years of distance between them.
However, a misunderstanding takes root when Meera overhears a phone call in which Saravanan jokes that their relationship is a "project." She believes he never truly loved her and she ends the relationship in heartbreak.
Returning to the present, Saravanan and Partha arrive at the wedding, their stories spilling out as they drink and reminisce. Meera feels sympathy, but Mahendrakumar refuses a reunion, citing wedding costs and her prior consent to marry. Just as the couple seems ready to part, a local bigwig named Rajini Murugan Arya arrives with his girlfriend and a pregnant girl, exposing that Meera's groom Ashwin had abandoned the pregnant girl. Ashwin initially denies it, but under pressure, he confesses and reconciles with the pregnant girl. Rajini Murugan promises to cover the wedding losses, and as Saravanan leaves, Meera returns and reunites with him.