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, despite 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 director S. P. Muthuraman initially wanted Rajinikanth to play a small role in a low-budget film. But after meeting him, the duo found him to have "brightness" and decided to cast him in "something bigger, better". The film was Bhuvana Oru Kelvi Kuri, an adaptation of the novel of the same name by Maharishi. Produced by Arunachalam who also wrote the screenplay, it was the first collaboration of Rajinikanth and Muthuraman. This film had a role swap as Sivakumar, then known for playing clean and positive characters, played an antihero while Rajinikanth, then an established villain, played a positive-minded person. Muthuraman said he deliberately cast Rajinikanth against type since he wanted to "experiment with his acting skills". He also explained that his decision to shoot the film in black-and-white, rather than colour, was budget-related since "colour film had to be imported and was very expensive". Since Rajinikanth was not fluent in Tamil at that time, he was trained by S. L. Narayanan, who was popularly known by the prefix "Vaadhyar".^[11] The final length of the film measured 3,976.12 metres (13,045.0 ft).^[1]

Ilaiyaraaja composed the music for the film.^[12] The song "Vizhiyile" is set in the carnatic raga known as Natabhairavi,^[13] and "Poo Thendrale" is set in Rageshree.^[14] In June 2013, A. Muthusamy of Honey Bee Music released a 5.1 surround sound version of the soundtrack.^[15]

Bhuvana Oru Kelvi Kuri was released on 9 September 1977.^[16][17] It won the Filmfare Award for Best Tamil Film and Muthuraman won the Best Tamil Director award at the same ceremony.^[18] Rajinikanth's performance won him the Thirai Kathir Award for Best Supporting Actor.^[19] In 1978, Film World stated that although Bhuvana Oru Kelvi Kuri dealt with social questions, it "neither had the motivation nor the justification very much essential to make a film realistic; at best [it] appeared frivolous."^[20]

The success of Bhuvana Oru Kelvi Kuri paved way for Rajinikanth the opportunity to do more hero oriented films.^[9] Although Sivakumar's fans disliked seeing him play a negative character, he received numerous offers to play negative roles following this film's success, and felt accepting to play Nagaraj was a mistake.^[21] Film producer and writer G. Dhananjayan wrote that it is one of five films Rajinikanth 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).^[22]