For Mithran (Jayam Ravi), the protagonist of Thani Oruvan, a person's friend shows his character while his adversary shows his capacity. Mithran is a young IPS officer whose only goal in life is to find a worthy rival — a kingpin who is the root cause of all other crimes — and destroy him. He meets his match in Siddharth Abhimanyu (Arvind Swami, making a glorious return), an ambitious scientist-businessman, for whom money is all that matters. This is how Mohan Raja sets up the conflict in Thani Oruvan, an efficient thriller, which packs a mighty punch. Raja's films so far have been competent remake efforts, but nothing prepares us for the smart writing (the director has co-written the film with writer duo Suba, whose experience in pulp novels comes in handy as it did earlier this year in Anegan) and the sleek filmmaking we see here.

The plot kicks in once Mithran learns of Siddharth's plan of sabotaging a deal that would result in cheaper medicines for the poor and tries to thwart it without his knowing, but the wily Siddharth manages to succeed. Realizing that he has an opponent who will not stop until he is defeated, Siddharth begins a cat-and-mouse game with the cop. There are some terrific moments — the scene where an assassination plan swings both ways, the scene where Mithran discovers Siddharth has paid his place a visit, the scene where two lives depend on Mithran finding a bug, the scene where Siddharth negotiates with the chief minister. What is refreshing is that, to a large extent, Raja manages to avoid diversions in the form of romance and comedy. Mithran's batchmate Mahima (an ideal Nayanthara) is in love with him, but she isn't just a love interest. She is intelligent (a forensic expert) and fearless and an essential person in Mithran's battle against Siddharth. In fact, when he says that he is ready to give up his life in order to bring down Siddharth, it is Mahima who makes him see his flawed approach to stopping crime. Yes, we get some fun moments with Thambi Ramaiah, who plays Siddharth's father, but it is never at the cost of the narrative.

Thani Oruvan is a bit too long (Siddharth enters the picture quite late), there are leaps of logic (like the one involving a dubbed video evidence) that we are asked to turn a blind eye to, but such downsides are minimal. And even though it is a plot-driven film, the film gives us well-rounded characters, who lend the slightly far-fetched story plausibility. The film doesn't shy away from showing Mithran for who he actually is — an angry young man whose ideals have turned him into an almost psychotic person. Crime, for him, is an obsession. What keeps him grounded are his fellow cop friends and Mahima. Jayam Ravi's body language — the purposeful strides, the clenched fists, the stern face — displays the determination of the character but doesn't really capture the craziness of the character.

But Arvind Swami aces the role of Siddharth. He projects the insouciant arrogance that tells us not to be taken in by his classy style which hides the character's toughened hide, and it is no surprise that we even root for this character, the villain, when he makes his moves against the hero. 'Show me your enemy and I'll tell you who you are', the film tells us in the beginning. With Siddharth, the film shows that you could paraphrase that statement and get the recipe for a thriller — 'Show me your antagonist and I'll tell you how effective your film is'.