The film's story revolves around deva, a youngster whose mother wants him to become a government official. He, on the other hand, works for a smuggling group run by Arumuga Dass who has been his mentor and looking after him since childhood. Conflict occurs when Deva's archrival, Kamalesh opposes and tries to eliminate Arumuga Dass from the smuggling business. Who wins in the conflict forms the climax of the story.
Deva (Suriya) arrives at the Chennai International Airport after running an errand for Arumuga Dass (Prabhu Ganesan) of smuggling pre-release unlicensed movies on DVD. The two leave for their hideout and instruct Dilli (Karunas), a hearing-impaired assistant of Dass, to make copies of the DVD. Just when police crews arrive into their vicinity, Dass informs Deva and the rest to leave. Deva tells the others to leave while he quickly sets up the burning process. Deva also leaves the hideout just in time. However, the police officers arrive at the hideout, only to see the burning process of the DVDs complete. The police then seize the DVDs and computers. The inspector, who was a friend of Dass, tells him that he can close the case if one of Dass's men agrees to the crime. Deva attempts to go, but another man, Chitti (Jagan), who had no affiliation to them volunteers, takes the blame. Later, Chitti joins Dass's group and befriends Deva.
Dass is a diamond trafficker who smuggles diamonds from Africa. Deva's mother Kaveri (Renuka) does not appreciate his affairs with Dass, as she wants Deva, who holds a Master of Science degree, to have a government job. He occasionally visits home and her roadside grocery shop, only to get scoldings from his loving mother. When Deva is invited to Chitti's house, he gets impatient and knocks on the door. As the door opens, Deva slips and falls on the bed, expecting to see Chitti but scaring his younger sister Yamuna (Tamannaah) instead. Just before he drives off, he curses himself for making such a stupid mistake. Yamuna catches this and accepts his apologies, then they slowly fall in love, their relationship is accepted by Chitti . Meanwhile, Kamalesh (Akashdeep Saighal), the arch-enemy and competitor in smuggling of Dass slowly starts to try to foil Dass and his employees. A prank phone call from Chitti leads to a near-death experience for Deva and Kaveri. Escaping alive and outraged, Deva goes and confronts Chitti, releasing his anger to the full extent. Chitti then reveals that he was Kamalesh's personal spy and that even though that their bosses were foes, he was happy to be a friend of Deva. Disgusted, he leaves and Chitti too, and at that moment, Yamuna arrives, hearing everything. Thus, this stir of events causes the interval of the movie.
After these events, Deva and Yamuna break up. In Malaysia, under circumstances, Chitti and Deva meet. Chitti, who was fed with drugs fall prey to them and starts reacting. In a last attempt to rekindle their friendship, Deva attempts to save him. Chitti then explains that it was wrong of him to be a spy, but still admits that he was lucky to have him as a friend. He dies when Kamalesh's henchmen try to salvage the drugs by cutting him open. Heartbroken, Deva returns to India.
When he arrives, Yamuna approaches him and asks the police officers to arrest him. But she notices Chitti's phone which he recorded a video before dying, brings it out , which contains a recording how Chitti died, also she sent the video to Dass. It is here clear that Deva didn't kill him, but hid from Kamalesh's henchmen. Yamuna apologises to Deva and the two come together again. Then later circumstances force Deva to become a part of the security squad in the airport as he is accused by Parthiban (Ponvannan), Assistant Commissioner of Income Tax Air Intelligence Unit of carrying drugs. He denies it, saying that the packet of drugs was given by a passenger's relative as she had forgotten it. The drugs are opened and it is found that heroin is sealed in them. Deva then realises and explains that huge amount of drugs are being transported by distracting him with a small amount. The flight is delayed and all passengers are asked to take food from the canteen. There are a few who don't do so, and hence their stomach is X-rayed and a huge packet of heroin is found. Then Deva is asked to help Parthiban and the Customs for arresting Kamalesh.
Deva and Parthiban put a cab like room outside Kamalesh's house and with Yamuna's help, a transmitter is put in Kamalesh's study. Then, all his conversations with his clients are recorded but Kamalesh later finds out and attempts to kill them, which fails. He later finds out that idols made of heroin are compressed under high pressure to disguise their smell and properties. With this evidence, the Income Tax comes to raid Kamalesh's house but he acts quickly and removes all the stuff. During a final attempt to arrest Kamalesh, the truth is forced out of his accountant but Kamalesh kills him to avoid any witnesses. Later, Deva's house is almost burnt and Dass is killed by Kamalesh, which infuriates Deva. He is then forced to go to Africa and confront Kamalesh.
When he returns to India, he is again inspected by the Custom Officer. Deva learns that it was his mother this time who exposed his smuggling mission. He has no choice but to surrender the diamonds, and so he does. Parthiban hands Deva to sign a form, which Deva hesitates. He then learns that is a government security job application form. Parthiban says that Deva's criminal mind is required for such a job in the Customs. He then asks what had happened to Kamalesh to which Deva replies that he had gone to Congo only to get revenge on Kamalesh. Then a flashback shows that when Kamalesh was returning from stealing the diamonds, his gang is killed by Deva and he is pushed off the cliff. The film ends on a happy note as Deva leaves the airport with his mother and Yamuna.Suriya as Devaraj Velusamy, a graduate in computer engineering and involved in smuggling to help his father's boss Dass.Tamannaah as Yamuna, Chitti's sister and Deva's love interest.Prabhu Ganesan as Anthony Dass, a local smuggler who starts with Kamalesh's father. Later become a number one.Akashdeep Saighal as Kamalesh, Dass's enemy in business.Jagan as Chitti Babu, Deva's friend and later revealed Kamalesh's spy in Dass group.Karunas as Dilli, Dass driver.Ponvannan as Parthiban IRS, Customs Officer.Renuka as Kaveri Velusamy, Deva's mother.Delhi Ganesh as Narcotics OfficerJanaki Sabesh as Lady at the AirportKalairaniKoena Mitra in a cameo
Three years after the release of his debut venture Kana Kandaen starring Srikanth and Gopika, cinematographer K. V. Anand expressed his desire to commence his second film as director. He and Subha discussed several plots and settled for "Ayan" because "it was not only different but had scope for entertainment". It was later announced that Anand would be directing his next film, produced under the AVM Production banner, titled Ayan. The film was inaugurated at AVM Studios on 24 March 2008 with the presence of most of the unit members. On the occasion, Anand announced the film's Genre to be an action thriller interlaced with romance and comedy. He also suggested Ayan meant "outstanding", excellence" or can be the name for sun rays in five different languages. However, this was later doubted by a few critics, raising a point saying Ayan was not necessarily a Tamil language word. Despite the film's lyricist Vairamuthu's calls for the word to be a Tamil word, it was argued that Ayan was a nickname for the Hindu deity Lord Brahma. Since the word was then touted to be borrowed from the Sanskrit language, the film was prone to a title change, in light of Tamil Nadu's Entertainment Tax Exemption Act, which was passed in 2006. A similar problem was faced by the producers of Aegan, which was also under production at the time. The controversy was later dropped. Ayan was announced to be predominantly set in various locations of both South Asia and Africa. It was made at a production cost of ₹ 200 million.
K. V. Anand announced the film with both Surya Sivakumar and Tamanna Bhatia to play the lead roles in the film. Surya was initially expected to play the lead role in Anand's earlier film, but was not able to do so. Anand expressed his thoughts during the film's inauguration that "Surya was apt for the title role" since the film's title meant "sun rays" and the name "Surya" refers to the sun. Ayan would also make Surya's second film with AVM Productions, after their previous partnership in Perazhagan. Furthermore, Surya had worked with Anand since Surya's debut in the 1997 film Nerukku Ner for which Anand was the film's photographer. Surya's physique was key for his character, as he would be acting as a powerful and active youngster. During the film's launch, he announced that he would give the film his best, understanding the nature of the producers, who previously presented the big-budget film Sivaji. Tamanna, after starring in the Tamil films Kalloori (for which she was nominated for a Filmfare Award) and Padikathavan, was cast in Ayan. Prabhu Ganesan was consecutively cast in Ayan in a pivotal role, as per his previous films, in which he played important supporting characters. It was later announced that Anand would introduce a new actor to Tamil cinema in the film, who will be playing a negative role, which was later known to be Akashdeep Saighal, who predominantly works in Bollywood films.
Apart from the film's cast, the film's crew consisted of Harris Jayaraj as the film composer along with Vairamuthu, Pa. Vijay and Na. Muthukumar as the lyricists. M. S. Prabhu was chosen as the film's cinematographer, who is a friend of Anand and worked with him under the guidance of P. C. Sriram.
Nenje Nenje’ song was shot on the Botswana-Namibia border, in freezing temperature. Songs were composed in Mauritius, where William Honk choreographed the car chase shots. The stunt sequences were shot at Binny Mills with a huge set resembling an airport while another fight was shot at Cape Town, Africa. The filming was also held at Kuala Lampur, Malaysia, Botsanwa, Zimbabwe and Zanzibar.
The film dealt with the concept of smuggling and custom officers. In order to prepare the script, Anand did a lot of research and is said to have spoken to a lot of custom officers to understand the modus operandi of smuggling.
The Soundtrack album was composed by Harris Jayaraj. The lyrics are penned by Vairamuthu, Na. Muthukumar and Pa.Vijay. The Times of India credited the popularity of the film to the popularity of songs. Critics were impressed with the album, with praise being dedicated to the entire soundtrack, most notably "Vizhi Moodi". Due to the album's critical and commercial success Harris Jayaraj received his fifth Filmfare Award for Best Music Director, the Mirchi Award for Best Album of the Year and the Edison Award for Best Music Director.
The satellite rights of the film were secured by Sun TV. The film was given a "U/A" certificate by the Indian Censor Board. AVM Productions sold the film's distribution rights for Tamil Nadu to Sun Pictures for ₹ 200 million.
Malathi Rangarajan of The Hindu wrote: "Ayan is Suriya’s show all the way. He bears the onus with a smile and the death defying stunts add to the robust image he aims to project". Behindwoods wrote: "Ayan is fun. Just buy a huge bag of popcorn, a can of cola and have a blast! But do remember the first step about the logic". Indiaglitz wrote: "Though the storyline is familiar and oft-seen in the past, the pacy narration and captivating visuals provide the necessary pep to the film".
In Chennai alone, box office totals were reported as ₹74.3 million (US$1.2 million) in theatrical revenue. International distribution rights were sold to Ayngaran International. Ayan's revenue was US$1,046,027 in Malaysia and £119,220 in the UK. The film's Telugu version, Veedokkade, was sold to Hyderabad based Producer, Bellamkonda Suresh. The final worldwide box office was around ₹65 crore (US$10 million). The film ran over 100 days in Kerala box office. , the telugu version Veedokkade ran over 100 Days in Andhra box office and ran over 201 days in Tamil Nadu.
Ayan received the most nominations (12) in the Filmfare Awards South 2009 and in the 4th Annual Vijay Awards (18).