Sudhakar Prabhu is a wealthy landlord. He throws an Onam feast at his house. Sathi, the daughter of an old servant, has also been given refuge in Prabhu’s house. Gopi Mohan, the estate manager, has his eye on Prabhu’s wealth and he seduces Sarojam, Prabhu’s sister, to acquire their riches. Sathi is in love with Chandran, a beggar involved in a movement to rehabilitate beggars. Prabhu supports his endeavours, but he is upset when he learns of his relationship with Sathi.
When Sarojam is pregnant, Gopi Mohan abandons her and begins an affair with Anandam, a sex worker. When Prabhu learns of this, he throws Gopi out of the house. Sarojam delivers a child in the house before she runs away. By the time Prabhu consents to Sathi’s relationship with Chandran, the latter has begun to suspect an illicit relationship between Sathi and Prabhu. After many travails, the lovers are finally united. Sarojam returns to a reformed Gopi Mohan, and Prabhu’s elder brother is discovered and returned to his own home. Sathi and Chandran leave together to pursue their goal of rehabilitating the beggars.
Yachakan is an adaptation of Dr. P.S. Nair’s novel Paradesi. Nair wrote the script and dialogues for the film as well. The film was Velappan Nair’s debut as a director. Previously, he was a renowned cinematographer. The film was shot at Rathna Studios in Salem. The film featured MP Manmathan, freedom fighter and leader of the Sarvodaya movement in Kerala. There are 18 songs in the film, including one by the renowned poet and freedom fighter Bodheswaran.