The plan of Zira, to kill Kiara and Nala.
Kovu not accept killing Kiara and Nala, Zira then asked to Nuka killing two, while Vitani put fire in the countryside where Nala encinas hunting to Kiara
Nala smelled smoke, and when he looked forward, flames were coming quickly toward the two. Nala and Kiara were already surrounded by flames everywhere. Suddenly the two fainted from inhaling too much smoke.
Simba saw the flames in the field where Kiara and Nala were hunting, ran straight to it, save it.
Kovu gets on the field, thus seeing Kiara and Nala passed out and I want to help them, but I could not save both.
Simba Arrives and sees Kovu with Nala the back, he roars to Kovu and then, Kovu if you explained to Simba. As the fire was already taking the whole field, Simba gave Permissions to Kovu to help you save them. Simba gets KIara on your back, and they come out running to the Land of the Kingdom.