Meet Rahul (Tushar) and Karan (Ritesh). Two young men who have come to the city of dreams to make it on their own steam. Not exactly diaper buddies but definitely thick friends. Rahul is simple and hardworking and Karan is just opposite. However, they share one thing in common. Both are wannabes trying to become famous fashion designer someday. Karan dreams of marrying a girl with a pretty face and a prettier bank balance.
Meanwhile, the city is rocked with a series of rape & killings & the police are in search of this dreaded Serial Killer. Things take a funny turn, when Rahul becomes the prime suspect as the serial killer and this sets the police on the trail. They hatch a plan with the help of a famous criminologist (Anupam Kher) to nab him in action. The job of nabbing Rahul in action is entrusted to a violent lady Inspector Urmila Martodkar (Isha Koppikar).
Meanwhile Karan, the wannabe Casanova, has managed to woo his boss's ex-girlfriend called Kiran. Kirna's parents plan to separate the two and for that they call Kiran's cousin Rekha (Neha Dhupia), a psychologist for help.
A complete laugh riot and a thorough entertainer, the film reaches its crescendo when the police are on the verge of arresting Rahul as the rapist and Karan is about to wed Kiran at the temple...
What happens next?
Do the mistaken identities fall into place?
Is the police able to nab the REAL Killer?
"KYAA KOOL HAI HUM" with its marathon cast of an entire comedy brigade, is a roller-coaster ride of mistaken identities, comedy of errors & deals with the basic spice of life...
(From the official press booklets)