Manithan is a 2016 Indian Tamil-language legal thriller film directed by I. Ahmed. The film features an ensemble cast, including Udhayanidhi Stalin, Hansika Motwani, Radha Ravi, Prakash Raj, and Vivek. Aishwarya Rajesh, Krishna Kumar, and Suraj play supporting roles. Music composed by Santhosh Narayanan. Cinematography handled by R.Madhi and Edited by J. V. Manikanda Balaji. Produced by Udhayanidhi Stalin, Co-produced by R.Arjundurai and M.Senbagamoorthy. Distributed by Fox Star Studios.

Plot:

The film begins with a drunk Rahul Dewan (Suraj), racing in a Toyota Land Cruiser Prado against an Audi, after he is seduced by a woman in the passenger seat. He loses control and crashes into a wall on the footpath by the road. The film cuts to a court scene where Sakthivel aka Sakthi (Udhayanidhi Stalin), an LLB (law-degree) graduate defending a surgeon against a Public interest litigation (PIL) filed against him after the surgeon had his son operate upon a patient in his pursuit of Guinness Book of World Records. Sakthi loses the case but decides to move to the capital Chennai to try his luck. He happens to see prominent criminal lawyer Adhiseshan (Prakash Raj) defending Rahul Dewan in a sessions court. Rahul Dewan is accused of causing death under the influence of alcohol. 

Adhiseshan convinces the judge that prosecution had no evidence to implicate Rahul Dewan and he was being deliberately targeted by the media as he was from a rich family, resulting in Dewan's acquittal. Adhiseshan, though, is not satisfied with the fee paid by the Dewans. Sakthi, desperate to have some money and fame, decides to pursue the case and files a PIL in the court against Rahul Dewan's acquittal. After initially reprimanding Sakthi for his mistakes in filing the PIL and taking the press reports as an evidence, Justice Dhanapal (Radha Ravi) gives a date for hearing and warns Sakthi to collect some evidence before the hearing. He then runs into Vijay Nair (Krishna kumar), who claims to have witnessed the accident. Then Sakthi introduces him as a witness in the court and Judge Dhanapal, after cross-examining him, gives a date for the next hearing. He also summons Rahul Dewan to be present in the court for the hearing. Sakthi becomes a celebrity overnight and is admired by Moorthy who donates a room in his restaurant to Sakthi for using it as his office. However, 

Sakthi's plans turn upside down, when Vijay nair reveals to him that he is no witness, but a crony of Adhiseshan and it was part of a plan to extract more money from Dewan clan. As part of the deal, Nair gives Sakthi his share of the money paid by Dewans to silence Nair. Sakthi gleefully accepts the money and regrets that had he known this plan earlier, he would have demanded more money. Vijay nair turns hostile in the court and Sakthi accepts the statement given by Nair. Judge Dhanapal postpones the judgement for the next hearing. Priya(Hansika Motwani), cousin and fiancee of Sakthi, chides him for compromising on justice for his greed. Sakthi realises his mistake once. Moorthy slaps him for his treachery. He returns the money to Adhiseshan and challenges him to win the case.

With the help of his uncle (Vivek), he collects the video footage of the Land Cruiser involved in the accident and presents it to the court. Though Adhiseshan counters him that the Land Cruiser was driven by the driver of Dewan family, Sakthi refutes his statement by submitting the necessary evidence. Judge Dhanapal orders the Police to provide a bodyguard for Sakthi after he was seriously beaten up by alleged assistants of Adhiseshan. Sakthi and his friends try to interview a relative of one of the victims, Muthupandi, but he says that he knows nothing. Sakthi and Priya decide to leave, but as they get on the scooter, a lorry hits them, injuring Priya. At the hospital, the Muthupandi tells Sakthi that a survivor of the accident stays in Vandavasi and Sakthi and one of his friends decides to leave for Vandavasi. 

Inspector Selvam tries to sabotage Sakthi's investigation, but is rescued by his bodyguard. Sakthi and Jennifer arrive at Vandavasi, but the police, who captured Muthupandi, kidnap the survivor. The next day, Sakthi reveals that he brought the survivor, thanks to Muthupandi intentionally showing the police the wrong guy, and Sakthi prosecutes inspector Selvam and finds that he has botched up the investigation by declaring Kamalakannan as dead and snatching Kamalakannans hard-earned money to stop him from killing Kannan.

Kamalakannan testifies that he woke up that night to see his family lying in pool of blood and Rahul getting out of the car, and after seeing what he has done, Rahul spotted Kamalakannan and ran him over, so no there will be no witnesses. Kamalakannan survived, with his leg being broken. Dhanapal tells Rahul to come to the podium and orders Kannan to see if Rahul was the driver. Kannan confirms that Rahul was the one who drove the Land Cruiser. After conclusion of arguments and counter-arguments between Adhiseshan and Sakthi, Judge Dhanapal directs Tamil Nadu Police to suspend inspector Selvam and initiate a criminal inquiry against him and also declares Rahul Dewan as guilty of the crime and sentences him to fourteen years in jail under Section 304 and under section 307 of the Indian Penal Code. The film ends with Sakthi celebrating with his team while Adhiseshan is crestfallen as he suffers defeat after a long time.