One Two Three revolves around three Laxmi Narayans who create a lot of confusion because of the similarity in their names. In addition to that, Diamonds worth ten crores are stolen from a certain Don, Papa. The diamonds accidentally fall in the hands of young lovebirds - Chandu (Upen Patel) and Chandni (Tanisha), who quickly hide them in a car. Papa and his idiotic henchmen Albert (Vrijesh Hirjee) and Pinto (Manoj Pahva) are desperately hunting for the diamonds while hot headed police officer Mayavati Chautala (Neetu Chandra) is on the prowl looking for offenders of any kind.
The first Laxmi Narayan (Tusshar Kapoor). He's from a ‘khandani’ mafia family and