With a plot that could be described as Aalavandhan meets Funny Games/Naanal meets The Dark Knight (the director credits Aalavandhan, Babel, Oldboy and Tarantino's films as his influences), Raghavendra Prasad's 54321 holds promise in its first half an hour. Anjali (Pavithra) is staying in a lonely house. Her husband Vinoth (Aarvin) is on his way home. A thief (Jayakumar) breaks into the place. And soon, another man enters, but with a sinister motivation. When Vinoth comes home, he finds the house in disarray. Soon, he comes face to face with the intruder, Vikram (Shabeer), with whom he shares a past. And Vikram wants Vinoth to murder a little girl he has kidnapped if he hopes to save his wife!

This is the film's best stretch. It sets up the story and is also suspenseful. But then, we start getting the backstory — why is Vikram targeting Vinoth, why is the thief here, how did Vinoth and Anjali fall in love and so on — and the answer to each one of these questions is a disappointment. The romantic track is terribly corny, the story of the thief uninspiring while his actions in the present-day are unconvincing, and the Vikram-Vinoth conflict is feeble (a childhood rivalry). And the acting gives us the impression of watching a short film.

Prasad does manage to compensate for the deficient writing through his filmmaking — the setting is largely a single room, but the director never makes us feel as if we are watching a video recording of a stage play. He keeps cutting from one character to the other in unpredictable ways to keep us on an edge, and the camera movements are quite fluid. One particular device he uses is the freeze frame every time he wants to cut to the flashback, though it gets tiresome after a point.

But what is troubling is that the violence seems to be there just for the sake of it. Both Vikram and Vinoth's characters are underdeveloped. We hardly feel the dilemma that the latter undergoes. And the film, too, never truly addresses the moral question at the heart of its plot — what makes one evil and is there difference between one evil act and another.