Dr, Rohit Mehra (Hrithik Roshan) , his son Krishna aka Krish (Hrithik) and Priya live together happily. Krishna keeps losing one job after another, as he is preoccupied with saving the world as Krish.

Their peaceful lives are disturbed by Kaal (Vivek Oberoi). Kaal is a brilliant but evil scientist who experiments with mutation, DNA fusion etc. In order to increase the profits of his pharmaceutical company, he unleashes a deadly virus on Mumbai and only he has the antidote.

But Kaal’s plans are disrupted when Dr. Rohit Mehra succeeds in coming up with a plan that stops the virus in its tracks. An enraged Kaal wants to find out how Dr Rohit succeeded in coming up with an antidote and he dispatches his evil aide Kaya (Kangana Ranaut) to find out the truth.

Unexpected things are revealed in the process and Krish must now fight for his family and stop the evil Kaal. How he does that is what ‘Krish 3′ is all about.