In Madurai, veteran rooster trainer Pettaikaaran (V. I. S. Jayapalan) and police inspector Rathnaswamy (Naren) are tough competitors in cockfights, and it is often Pettai who wins because nobody knows his way of maintaining the quality of the birds.
Karuppu (Dhanush) and Durai (Kishore) are the favourites in Pettai's team. Karuppu is very talented in breeding and training roosters, while Durai is very rich, owns three bars in Thiruparangundram town, and is also talented in cock training. Rathnasamy keeps insisting on having one last fight to win and satisfy his old mother’s wish, but Pettai declines to have any more fights with him because he feels Rathnasamy has lost faith in his roosters and will be using nefarious methods to win. Rathnasamy keeps insisting and tries to make him accept the challenge through cajoling, threatening, bribing and other vile acts.
Karuppu falls in love with an Anglo-Indian girl Irene (Taapsee) who dislikes him. He does not recognise this initially and keeps following her. One day the residents of Irene's colony confront him and ask Irene to tell who she is in love with – Karuppu or Dinesh (Dinesh Ravi), another man in the locality. She points her finger at Karuppu and he goes into rapture. She explains later that she had to lie in order to avoid Dinesh who has been bothering her for a long time. Later, Irene too falls in love with Karuppu.
Meanwhile, one of Pettai's close associates, ayubh, his veterinarian for roosters, is killed in a hit and run accident. Durai initially suspects rathnasamy, and all of pettaikaran's gang want revenge. But Pettaikaran says they have conduct a tournament in Ayubh's name and provide his family with funds, so that ayubh's daughters can be married. He asks permission from rathnasamy, as police have to permit, but rathnasamy refuses and berates pettaikaran as a thief. In a rage Pettai, suspecting Rathnasamy of the murder, agrees to the one-on-one rooster fight rathnasamy has been asking for so long. He bets that , he will field roosters against all of rathnasamy's roosters in the following tournament. Even If one of Pettaikaran's roosters loose against rathnasamy's, he will tonsure his head and face, publicly apologise to him, and will quit rooster fights. But , if rathnasamy is not able to beat any 1 of his roosters, same conditions will apply on him, at the end of the day. Finally getting his way, rathnasamy permits the tournament.
The grand state tournament is arranged by Pettai's team, getting funds and official permission. In the crucial fight, Rathnasamy brings high breed roosters from Bangalore. Karuppu asks Pettai to let his rooster fight but Pettai puts his rooster down and says he will choose the best competing rooster himself. Karuppu surreptitiously enters the contest as Pettaikaran's team before Pettai can choose the rooster because he needs to repay Irene for the loan he took to prepare his rooster for the fight. Pettai does not believe in Karuppu and his rooster and announces that Karuppu will not represent Pettai and the result of Karuppu's match will not be acknowledged by his team. The 'underdog' however emerges victorious in three consecutive rounds despite facing roosters spiked with steroids. Karuppu gets the best coach award of the tournament and his bet money of 3 lakh 1o thousand₹10 lakh (equivalent to ₹14 lakh or US$22,000 in 2016).
While initially happy that Karuppu won, Pettai is soon overcome with anger and jealousy. His ego is hurt by the fact that Karuppu earns both popularity and money, by refuting his judgement. Karuppu is not aware of the changes in his mentor's mind. Pettai is at first he refuses to speak to anyone and then starts scheming. The money from the competition that Karuppu gives to Pettai for safe keeping, that he plans to use to start a business, suddenly goes missing. Pettai also starts spinning stories about his associates and makes everyone suspicious of each other. He incites Karuppu and Durai into pitting their roosters in a fight. Meanwhile, Karuppu's mother dies from the shock of losing all the money. Meanwhile, Pettai poisons all of Durai's roosters making him suspect Karuppu, who is arrested for this. Pettai then lies to Irene that his wife was in an adulterous relationship with Karuppu. Irene's family also pressure her to move to Chennai which pushes her into attempting suicide. Pettai meanwhile calls Karuppu to a location near a temple and informs Durai about his whereabouts. When Irene gets better, she calls Karuppu and informs him that Pettai is badmouthing him. So Karuppu goes to find Pettai and confront him. Karuppu finds that Pettai was the one who stole his money, and a guilt-ridden Pettai kills himself. Karuppu does not wish to reveal the fact to the public that his mentor was the criminal who stole his money and schemed against him, so he flees with Irene to start a new life in another city leaving the money with his friend.Dhanush as KaruppuKishore as Durai (Voice-over by Samuthirakani)Taapsee Pannu as Irene (Voice-over by Andrea Jeremiah)V. I. S. Jayapalan as Periyasamy/Pettaikaran (Voice-over by Radharavi)Naren as RathnasamyMeenal as MeenaMurugadoss as OoleSentrayan as NicholasJayaprakashPeriya Karuppu Thevar as AyubDinesh Ravi as DineshVelraj as Police Inspector (special appearance)
Following the success of their 2007 collaboration Polladhavan, the entire team of that film — director Vetrimaaran, lead actor Dhanush, producer S. Kathiresan, and music director G. V. Prakash Kumar — collaborated again for Aadukalam. Vetrimaaran spent a period of two years in Madurai to understand the local dialect and lifestyle of the people living there. Aadukalam was the first film of Vetrimaaran to have a production office set up outside of Chennai. Vetrimaaran took a year to complete the screenplay, script, and dialogues for Aadukalam and held a bounded script for the venture, which is considered rare in Tamil films. Vetrimaaran narrated only half of the film's script to Dhanush before the latter was impressed with it and agreed to act in the film. The film was initially titled Seval, but since the rights to the title were already taken by director Hari for his project with Bharath, Vetrimaaran decided to rename his film as Aadukalam.
Shriya Saran was signed on for the project in February 2008 but eventually pulled out citing schedule conflicts. In April 2008, it was reported that Dhanush too had walked out of the project due to schedule issues, and that Silambarasan was set to replace him. However, Dhanush remained and continued with the film. Subsequently, in June 2009, Trisha Krishnan, who was selected to replace Saran for the role of Irene, was forced to opt out of the project after her schedule clashed with the allotted dates for her other films, Namo Venkatesa (2010) and Vinnaithaandi Varuvaayaa (2010). Newcomer Taapsee Pannu, a Punjabi software engineer, was named as her replacement. Taapsee Pannu is casting by Varun Adlakha casting director Delhi / Mumbai. Sri Lankan Tamil writer and political commentator V. I. S. Jayapalan portrayed the role of Karuppu's mentor, Pettaikaran, thereby making his debut in Tamil cinema. Attakathi Dinesh makes a small cameo in the film as Dinesh, Karuppu's nemesis when it comes to winning Irene's love. Murugadoss plays Karuppu's friend Oole while Naren appears as Rathnasamy who is also Pettaikaran's rival in cockfighting.
Principal photography began in Madurai in February 2009 with scenes featuring Dhanush being shot. The first look of the film was released shortly after the commencement of filming. It featured a series of promotional posters depicting the characters played by Dhanush, Jayapalan and Kishore. During early stages of production, Dhanush revealed he would play the role of a local cockfighter named K. P. Karuppu, and described the venture as his "dream project". The cockfight sequences that take place before intermission was filmed for 26 days in a set created by art director Jacki. Filming was completed in August 2010. In addition to being shot in Madurai, some portions were also filmed in Thiruparankundram. The cockfights were filmed using Computer-generated imagery (CGI). The post-production works on the cockfight sequences delayed the film's release. The voices for Kishore, Taapsee, and Jayapalan were dubbed by Samuthirakani, Andrea Jeremiah, and Radha Ravi respectively.
G. V. Prakash Kumar's soundtrack consists of seven tracks including two rap numbers performed by Malaysian Tamil rapper Yogi B. It was released by Sony Music and the audio was launched at a small function at Lady Aandal School auditorium in Chennai on 10 November 2010. The song Yathe Yathe topped the charts and remained in the No.1 position for nearly five weeks.
Aadukalam received positive reviews from critics. Sify called it "a gutsy and brilliant film" and mentioned that it " lives up to the expectation that the film carried and the credit goes to Vetrimaran whose research and hard work shows on screen". Behindwoods wrote "Aadukalam is an attempt that requires appreciation where the director has hacked his way through the path less trodden with aplomb". Karthik Subramanian of The Hindu praised the film stating that "The detailing of every characters in the story is intricate. The narrative moves like a good novel where the first few chapters are all about etching and detailing the players, and the plot and the action unfold much later". Pavithra Srinivasan of Rediff.com called it "one of Dhanush's best works to date". Tamil magazine Ananda Vikatan rated the film with 44 marks and mentioned that "This arena is new for presenting cultural nuances of a region and changes in human emotions beautifully".
Aadukalam won six awards at the 58th National Film Awards ceremony, thereby sharing the record with Kannathil Muthamittal (2002) for the most number of National Film Awards won by a Tamil film. It won awards under the Best Direction (Vetrimaaran), Best Actor (Dhanush), Best Screenplay (Original) (Vetrimaaran), Best Editing (Kishore Te) and Best Choreography (Dinesh Kumar) categories with a Special Jury Award being presented to V. I. S Jayapalan. The film was nominated in seven categories at the 59th Filmfare Awards South, winning Best Film – Tamil (S. Kathiresan), Best Director – Tamil (Vetrimaaran), Best Actor – Tamil (Dhanush), Best Music Director – Tamil (G. V. Prakash Kumar), and Best Cinematographer (Velraj). At the 6th Vijay Awards, it was nominated in twenty-two categories and won in five, including Entertainer of the Year (Dhanush), Best Director (Vetrimaaran) and Best Music Director (G. V. Prakash Kumar). Among other wins, the film received seven Ananda Vikatan Cinema Awards, four South Indian International Movie Awards, three Mirchi Music Awards, and one Norway Tamil Film Festival Award, Chennai International Film Festival Award, and Chennai Times Film Award each.