Friends Nagaraj and Sampath are road-side garment salesmen living in Tirunelveli in the same house. While Sampath is a straightforward person who believes in honesty. Nagaraj is a womaniser who loves many women at the same time, in contrast to Sampath who believes in true love. Sampath's lover Raji, while fleeing from a rogue bull, dies due to an accident. A depressed Sampath attempts suicide, but Nagaraj stops him, and Sampath decides to stop selling garments, instead confining himself to remaining Nagaraj's assistant.
After Nagaraj and Sampath board a train bound for Madras as part of a business trip, they encounter Muthu, a temple trust clerk who has kept a lot of cash in a suitcase. But Muthu dies en route to Madras due to a heart attack, and Nagaraj takes the suitcase of cash, against Sampath's protests. Muthu's sister Bhuvana visits them in their Nagercoil house to enquire about the lost cash (which is all black money). Nagaraj denies knowing anything, but Bhuvana remains suspicious. He pretends to love her; Bhuvana falls for his lust and has sex with him.
Nagaraj uses some of the black money to open his own garment store. To make the rest of the black money legitimate, Nagaraj decides to marry Manohari, the daughter of a wealthy businessman. Bhuvana, having been impregnated by Nagaraj, refuses to abort the baby and wants Nagaraj to marry her, but he refuses to do so. To save Bhuvana's honour and to help his friend, Sampath marries Bhuvana but they only share a platonic relationship, while Nagaraj marries Manohari and his business flourishes.
Sampath wants to have a physical relationship with Bhuvana but she rejects him, saying he is like a god to her. Sampath raises Bhuvana's son as his own. Meanwhile, Nagarajan and Manohari yearn for a child as the former has now become impotent due to his excessive libido. Nagaraj demands that his son be given to him for adoption but Bhuvana refuses.
When the child becomes ill and needs an injection, Nagaraj enters into a bargain that he would give the medicine from his pharmacy, provided it is agreed that the child is given to him in adoption. But Sampath arrives on time to deliver the injection and the child is saved. However, following years of excessive smoking and drinking, Sampath succumbs to cardiac arrest. Bhuvana prefers to live as his widow.Sivakumar as Nagaraj
Rajinikanth as Sampath
Sumithra as Bhuvana
Jaya as Raji
Meera as Manohari
Y. G. Mahendra as Muthu
Panchu Arunachalam and S. P. Muthuraman initially wanted Rajinikanth to play a small role in a film called "Avalukku Oru Aasai" but after meeting him, the duo found him to have "brightness" and decided to make him a solo hero in their project. This film had a role swap as Sivakumar, then known for playing clean and positive characters, played a character with negative shades while Rajinikanth, then an established villain, played a positive-minded person. This role swap helped both the actors in experimenting the roles. The success of the film paved way for Rajinikanth the opportunity to do more hero oriented films.
Ilaiyaraaja composed the music for the film.
Bhuvana Oru Kelvi Kuri won the Filmfare Award for Best Film - Tamil. Rajinikanth's performance won him the Thirai Kathir Award for Best Supporting Actor.
In June 2013, A. Muthusamy of Honey Bee Music enhanced the songs from their original version on the film's soundtrack album to 5.1 surround sound. G. Dhananjayan wrote that it is one of five films the actor considers "close to his heart"; the other four are Mullum Malarum (1978), Aarilirunthu Arubathu Varai (1979) and Enkeyo Ketta Kural (1982) and Sri Raghavendrar (1985).