Hum Tum is a new and refreshing look at the eternal battle of the sexes as it follows the lives of karan (Saif Ali Khan) and Rhea (Rani Mukerji). Karan is a cartoonist and his cartoon characters "Hum" and "tum" are very popular. Hum Tum reflect Karan's Perspective on men and women and their strange relationship. Karan is the quintessential bad boy – he is a complete flirt, and is constantly changing girlfriends. Rhea is sensitive, well bred and with high ethical and moral standards. The two come from very different backgrounds, and have evolved into very different people. Where as Karan's Father – a flamboyant famous fashion photographer, has influenced his son to be nonchalant and "cool", Rhea gets her Self-assuredness and moral code From her a mother – a typical Punjabi with an effervescent spirit. They have very little in common, except the fact that, time and again, their paths cross. Across three continents, and over the period of nearly a decade, the lives of Karan and Rhea intersect, and their relationship evolves, from hate, to mutual friendship and respect and finally…. In a cinematic universe that offers simplistic scenarios to the complex and layered relationships between men and women, Hum Tum is a refreshing and realistic look at the trials and tribulations of "every woman" in their attempts to understand each other.