Two men waiting for a flight to Chennai at the Biju Patnaik International Airport in Bhubaneswar engage in conversation. One is a commercial director, Anbarasu, who prefers the abbreviated name A. Aras, and the other is a scarred and deformed socialist, Nallasivam, alias Nalla. When the flight is cancelled due to heavy rain, Aras initially suspects Nalla is a terrorist and informs the authorities, only to discover that he was mistaken. With the rain flooding the city, the two men are forced to share a room for the night. Both need to return to Chennai: Aras to be present at his wedding, and Nalla has to deliver a ?3,200,000 cheque, recently awarded to him after he won a court case, to a group of union workers. After a traumatic night, and no hope for a flight, the two men take a bus to board the Coromandel Express train. Aras' bag gets stolen on the way leaving him with only his credit card, which no one accepts. Using his presence of mind, Nalla repeatedly bails Aras out of trouble while Aras tries escaping from him at every juncture, only to end up with him again. While waiting for the train at the Ichchapuram railway station, Nalla begins to tell Aras his story.

A few years earlier, a healthy Nalla took part in various street theatre performances protesting against multinational corporation-driven industrialisation, that resulted in the marginalisation of the labour force. He was at odds with Kandasamy Padayatchi, a manipulative factory owner who refused to give his workers a raise. Nalla satirically imitated Padayatchi in many of his shows. However, in an unexpected turn of events, Nalla and Padayatchi's daughter Balasaraswathi alias Bala, fell in love with each other. To avoid a potential conflict with Padayatchi, the two decided to elope to Kerala. Nalla boarded a bus bound for Kerala, and on his way to meet Bala, the bus crashed on a hillside leaving him scarred, disfigured, and partially paralysed for life. After recovering from his wounds, he visited Bala only to be informed by Padayatchi that his daughter was already married and has settled abroad. Padayatchi had earlier lied to Bala that Nalla died in the accident. It was also at this time that Nalla became a firm believer in kindness and love. Despite suffering from an inferiority complex due to his scarred and deformed body, Nalla performs community service and social work with renewed fervour while continuing to fight for union causes.

Upon their arrival at Chennai, Aras delivers Nalla's cheque to the union workers. He invites Nalla to his wedding, where, to his utter astonishment, Nalla sees that Aras's bride is Bala. Padayatchi spots Nalla and asks him why he is at the wedding. He tells Padayatchi that he was invited by Aras, and later persuades him to sign the papers which will help the workers get a raise. To prevent the disruption of Bala's wedding and avoid damaging his own reputation, Padayatchi yields to Nalla's demands. After signing the papers, Padayatchi instructs his assistant to eliminate Nalla. However, his assistant has a change of heart as he is about to kill him. Padayatchi's assistant believes that the misdeeds he committed for Padayatchi resulted in the death of the assistant's daughter. Padayatchi's assistant requests Nalla to stay as far away from his boss as possible; Nalla assents and walks away.

• Kamal Haasan as Nallasivam alias Nalla
• R. Madhavan as Anbarasu alias A. Aras
• Kiran Rathod as Balasaraswathi alias Bala
• Nassar as Kandasamy Padayatchi
• Santhana Bharathi as Padayatchi's assistant
• Seema as Balasaraswathi's mother
• Yugi Sethu as Uthaman
• Uma Riyaz Khan as Mehrunissa
• Pasi Sathya as a tea stall owner
• Balu Anand as the train ticket checker for the Coromandel Express
• R. S. Shivaji as the Ichchapuram railway station master
• Ilavarasu as a police inspector and aide of Padayatchi

Development

After completing the draft for a film's script in early 2002, Kamal Haasan approached the Malayalam filmmaker Priyadarshan to direct it. The two men were keen to work together since the late 1990s, and upon reading the script, Priyadarshan believed that it had the potential to be an "emotional love story". The film's title Anbe Sivam was derived from the Shaivite saint Tirumular's poem Tirumantiram.

In June 2002, Priyadarshan opted out of the project. Regarding the director's exit, Haasan said Priyadarshan wanted to collaborate with him on a bigger project than Anbe Sivam. He was replaced by Sundar C., who agreed to produce the film as well. Anbe Sivam was co-produced and distributed by Swaminathan, K. Muralitharan and G. Venugopal under the production banner of Lakshmi Movie Makers.

Cast and crew

In addition to being the film's writer, Haasan also played the central character. R. Madhavan was selected to play the film's second lead in January 2002. According to Kiran Rathod, she received a phone call from Haasan's office informing her that she was offered the role of Balasaraswathi, which she accepted. Rathod's voice in the film was dubbed by the singer Anuradha Sriram. Uma Riyaz Khan played the role of Kamal's friend and professional colleague, Mehrunissa.

He came over to me and said, 'Madhavan, I have seen some of your work and they were good.' Then he continued, 'I have something for you. We should catch up!' that was how Anbe Sivam happened.

—?Madhavan on how he was cast in Anbe Sivam

The actors Nassar and Santhana Bharathi played the roles of Kandasamy Padaiyatchi and his assistant, respectively, while cartoonist Madhan featured in a cameo appearance as himself in addition to writing the film's dialogues. In an interview with S. R. Ashok Kumar of The Hindu in 2006, Bharathi considered both Anbe Sivam and Michael Madana Kama Rajan (1990) to be the favourite roles of his career.

Arthur A. Wilson, M. Prabhaharan and P. Sai Suresh handled the film's cinematography, art direction and editing, respectively. Brinda, Chinni Prakash and Dinesh Kumar were in charge of the choreography while the stunt sequences were co-ordinated by Vikram Dharma. Muthulakshmi Varadhan, Bharathi's sister-in-law, worked as an assistant editor in the film. The make-up for Haasan's scars was designed by Michael Westmore and Anil Premkarikar. In May 2002, Haasan completed the makeup for his character Nallasivam in Los Angeles after filming the song sequences for Panchathantiram (2002).

Filming

Principal photography for Anbe Sivam commenced in July 2002. The first scene featuring the lead actors was shot at Pollachi Junction railway station. Haasan and Madhavan interacted closely during the initial stages of the shoot to ensure that the on-screen chemistry between the pair was apparent.

Anbe Sivam was shot on a restricted budget of ?120 million, with the train and bus disaster sequences involving the use of settings and CGI. Madhavan, who began shooting his portions in September 2002, stated the film was shot in relatively empty locations. The flood scenes set in Odisha were re-created with outdoor sets consisting of city roads submerged under water erected in the Odisha-Andhra Pradesh border. Filming also took place in Chennai, Visakhapatnam and on the Tamil Nadu-Karnataka border. The pre-climax scenes were filmed in what was then known as the Campa Cola compound in Guindy.