Considering the love our heroes have for the masala genre, its no surprise that Karthi signed up for Siruthai, a remake of Ravi Teja's Telugu hit Vikramarkudu. With a dual role for him and ample opportunity for action, romance, comedy and sentiments, it must've been an easy choice. But one wishes he had also seen the crassness, violence and utter lack of logic in the film, that make us wonder if we've walked into a Sundar.C film by mistake.

Rocket Raja(Karthi) is a pickpocket and petty thief though Swetha(Tamannah) is unaware of this when she falls for him. Eager to turn over a new leaf because of Swetha, Raja goes looking for one last theft that would let him live happily ever after. But he ends up being saddled with a girl Divya(Baby Rakshana) who refers to him as her dad. As Raja bonds with her, he learns that her dad is a cop Ratnavel Pandian(Karthi) whose whereabouts are now known only to few.

Rocket Raja is an interesting character as he robs and has no qualms about teasing kids and raining blows on women. But the film doesn't exploit him well as his scams are silly and involve cheating some really dumb victims. A lot of the comedy is crass and the few scenes that work(like Karthi backstabbing Santhanam to facilitate his romance) aren't original situations. Tamannah's completely wrong opinion of Karthi leads to some smiles in their budding romance but the crassness soon finds its way into the romance also with Karthi having a weakness for women's waists.

The cop's segment follows the template of all honest cop vs bad guys stories as we see a brave, fearless cop cleaning up an area ruled by some ruthless villains. The showdowns between Karthi and the villains are energetic but the crassness that was in the romance and comedy now moves over to actions of the bad guys who are completely loud and over-the-top(for instance, their method of insulting policemen is to make them lose a running game and then undress them!). The film's tone also undergoes a big shift due to the violence that gets upped as Karthi wields a rather scary-looking weapon and mows down dozens of guys.

The way Baby Rakshana comes into Karthi's life is a nice surprise and their bonding provides the movie's softer, nicer moments. But past that, the film does nothing original or interesting in the way it utilizes Karthi's double role as one of them takes the other's place. This also leads to the movie's tone slipping back into light-hearted territory as the thief once again takes center stage. Unfortunately, this is done by turning the villains into comedians. After their ruthlessness and display of power earlier, it is absurd to see them reduced to helpless, lamenting caricatures as they are led on a futile chase by Karthi.

Karthi plays the thief with the right mix of charm and roguishness and the thinthaathaa bit is a cute signature. He has a bit more trouble with the cop role as his lack of experience comes in the way of him being convincing in the larger-than-life, supercop role. Tamannah is completely redundant and on board just for showing some skin. Santhanam gets some laughs when teamed up with Karthi but the comedy is too weak for him to do so consistently. Vidyasagar delivers a very weak soundtrack with none of the numbers making an impression.