Aasai

Yamuna, the younger daughter of an Orthodox father, travels to Madras to finish her studies. Major Madhavan, the husband of Yamuna's elder sister Ganga, spots her photo and becomes infatuated. He begins to weave a plan to win her heart while maintaining his image as a devoted family man.

Jeeva meets Yamuna in a bus and notices she forgot her ticket, so he lends her his. They share a moment of connection as they interact. This encounter marks the start of their budding relationship.

Jeeva tries to express his feelings by writing a letter for Yamuna, but witnesses a group beating a boy who did the same and disposes of the letter. Yamuna later finds the discarded letter and realises his love for her. The discovery becomes a turning point in their relationship.

While walking together, Jeeva tries to wipe dirt from Yamuna's eyes and ends up kissing her. He catches a cold after getting drenched in the rain, and Yamuna tends to him. He declares that she is his medicine and promises to marry her.

On Yamuna's birthday, Jeeva bursts into her home with a puppy, symbolizing their growing love. The gesture deepens their bond and commitment to each other. It becomes a turning point in Yamuna's feelings toward Jeeva.

To secure their relationship, Jeeva plans to marry Yamuna in a registry office. Yamuna refuses to formalize the relationship on that basis. Jeeva leaves in frustration as their path forward remains uncertain.

Madhavan settles his father-in-law's debts and earns trust by facilitating a landline connection to Yamuna's house. Ganga becomes aware of his true identity, realizing he is not the simple family man he pretends to be. Madhavan then expresses his love affair with Yamuna to his wife, upsetting Ganga and prompting her to consider leaving with their father.

Madhavan imprisons Ganga in their home and drugs her with sleeping pills, then suffocates her using a polythene cover tied with a shoelace. He fabricates a heart attack as the cause of death to cover his crime. The murder solidifies his hold over the family and shatters Yamuna's trust.

Madhavan moves Yamuna and her father to Delhi to look after his baby, revealing his broader plans. The relocation places them in a new setting where his manipulation can continue unchecked. The move signals a new phase in the sinister scheme surrounding Yamuna.

Jeeva arrives in Delhi and is initially spurned by Yamuna, but she gradually accepts him again. Two months later, Yamuna's father decides to arrange her marriage to Jeeva, seeing him as the rightful partner. Madhavan begins to counter these plans to protect his hold over Yamuna.

The family meets Jeeva in a restaurant where tensions flare and Madhavan manipulates events. In the melee, Jeeva’s purse is stolen, and he confronts the thief, unknowingly playing into Madhavan's hand. Yamuna's father, seeing only Madhavan's version, distrusts Jeeva.

Madhavan escalates his deception, even during Holi, where he takes the puppy and kills it to frame Jeeva. Hariharan eventually realises the truth about Madhavan and confronts him, but Madhavan kills Hariharan by staging a car accident. This marks a turning point as the web of lies tightens around Jeeva.

Madhavan plants narcotics in Jeeva's pillows and tips off the police, leading to Jeeva's arrest. While in prison, Jeeva confronts Madhavan and learns of his full treachery, while Yamuna overhears and informs her father, heightening the peril.

Jeeva escapes from prison and reaches Madhavan's house, where a fierce fight ensues. Yamuna's father locks the doors, opens a gas cylinder, and lights a match, triggering an explosion that kills both Madhavan and Yamuna's father. Jeeva is exonerated and reunited with Yamuna and the baby.