Trama

The Solaiyur Dam, which is the lifeline of the village of Solaiyur, is under assessment for structural integrity. The dam inspector is ordered to report that the dam is unfit to remain, and the corrupt local MP Nagabhushan, wants the dam demolished for his benefit. When the former refuses, Nagabhushan stabs him to death. The dying man throws a pen drive (disguised as a rudraksha) containing the details certifying the dam's integrity, into an abandoned Shiva temple near the dam and warns the village head Karunakaran, who arrives upon hearing his cries, that the temple has to be opened as soon as possible, before dying. Karunakaran firmly believes that the temple can only be opened by the descendant of Raja Lingeshwaran, an erstwhile king who built the dam as well as the temple. Lakshmi, the granddaughter of Karunakaran and a journalist, embarks on a search to find the descendant. She soon discovers the person - Lingeswaran aka Lingaa. Lingaa, the grandson of Raja Lingeshwaran, is a witty thief, living in poverty. He bears a grudge against his grandfather, firmly believing his "squandering nature" is the root cause of his poverty. Consequently, he refuses to accompany Lakshmi to Solaiyur.

Undeterred, Lakshmi follows Lingaa and records his gang's act of stealing a priceless necklace and implicates them, thus forcing him to accompany her to Solaiyur. At Solaiyur, Lingaa receives a warm welcome from the villagers. Later, Karunakaran privately tells Lingaa that the Lingam installed at the Shiva temple is made of Emerald stone, an extremely valuable artefact. At midnight, he infiltrates the Shiva temple to steal the Lingam. Unfortunately, he is noticed by one of the dam's security guards, who immediately alert the villagers. Aware of their presence, Lingaa quickly and wittingly changes his act to an appearance of performing a pooja, thus fooling the villagers. A relieved Karunakaran then narrates the true story of Lingaa's heritage.

Raja Lingeshwaran, the ruler of the erstwhile princely state of Kodiyur, is shown to be a civil services officer and the collector of the Madurai district. Upon surveying the village of Solaiyur, he receives complaints from the local villagers, stating that they have no water for nine months per year while facing raging floods for the other three months - which has led to recurring and devastating famines. Determined to help, he petitions to construct a dam, for the benefit of Solaiyur. However, his plan is rejected at the annual collectors' meeting and he is instead forced to approve another infrastructure project. He refuses to do so and is blackmailed for being dismissed for his non-compliance. In defiance, Lingeshwaran resigns from his position.

Later, several members of the Indian royalty and British officers congregate to celebrate Lingeshwaran's birthday. Among them is Collector Lawrence Hunter, the officer who had opposed Raja Lingeshwaran's plan. He is shocked to discover Lingeshwaran's real identity. Over dinner, Lingeshwaran notifies the British Governor of his resignation and expresses his wish to construct a dam at Solaiyur, with his capital. He requests approval from the British Government, which is granted. The Collector challenges Raja Lingeshwaran that he will never finish building the dam. Though Lingeshwaran faces multiple difficulties and a near stoppage of work due to caste issues (which were ignited by Sambandam, a resident shown to be working as a spy), the dam is constructed with the help of the villagers, who turn out to be very co-operative with Lingeshwaran. Bharathi, the daughter of a senior villager falls in love with Raja Lingeshwaran. Finally, the dam is almost complete, except for the shaft doors. The doors are found to be held in the collector's possession. With the floods soon to occur, Lingeshwaran negotiates with the collector and tries to persuade him to give in. As a dirty trick, the latter proposes that if the shaft doors are to be handed over, Lingeshwaran must hand over the villagers' land as a bribe and the credit for constructing the dam, to which he reluctantly agrees. Sambandam discreetly brings the villagers to the collector's residence at the same time and tricks them into believing that Lingeshwaran is a puppet of the British, thus manipulating them.

After the dam's completion, the infuriated villagers reprimand Lingeshwaran for his "malicious actions" and banishes him from Solaiyur, despite Bharati's protests. Fully knowing the double-play behind him, Lingeshwaran leaves and is later accompanied by Bharati. The collector's wife, Jenny, disgusted at her husband's behaviour, angrily reveals to the villagers that they have been double-crossed and reveals the real terms that Lingeshwaran had agreed to. The villagers, upon realizing their double play, pursue Sambandam, who commits suicide out of guilt. Jenny decides to leave with her daughter but is stopped by her husband, having realized his folly. Upon her insistence, he publicly declares that the dam was constructed by Lingeshwaran. After a long search, the villagers find him and Bharathi, now his wife, living in poverty. After unsuccessfully trying to convince him to return to Solaiyur, the villagers resolve to keep the Shiva temple (which he had built), closed until the Raja or his descendants return to the village. Lingaa, on hearing his grandfather's story, changes his opinion about his grandfather and decides to mend his ways.

In the present, Karunakaran reveals that his invitation to Lingaa was merely a ruse, as he believes that danger is afoot; recalling the fate of the dam inspector. At a function, Nagabhushan reveals to an accomplice that he plans to drill small holes into the dam, which would be filled with explosives; when triggered, would destroy the dam. Lakshmi secretly records Nagabhushan's conversation with the help of a spy camera and plays it before the entire town, exposing Nagabhushan. Lingaa then reveals that he had already discovered the pen drive and had the dam's certificate approved, copied, and spread throughout the Internet; ultimately culminating in Nagabhushan being ousted from his position. Enraged, he kidnaps Lakshmi and escapes in a hot air balloon. Having a bomb with him, he plans to detonate it over the dam, to spite Lingaa. Lingaa pursues him on a bike and drives it over a ledge at the exact time Nagabhushan's balloon appears on it, landing on top of it; he manages to climb into the carriage. After an ensuing fight, he kicks Nagabhushan out, who plunges to his death in the water below and kicks the bomb into the reservoir, which explodes moments later, thus saving the dam. With his work done, Lingaa plans to leave. However, the police finally catch up to him, demanding that he testify for an inquiry (about his recent jewel heist). Just before leaving, they are joined by Lakshmi, having fallen in love with Lingaa.