Answer and Explanation:
In "Mockingjay" we can see the revolt of the districts in relation to the abuses promoted by the capital. In that book we learn that District 13 does exist and that the revolution has started there. Katiniss agrees to join the group of rebels that will provoke the revolution and begins training in the rebel army with her friend Gale.
At the moment Katniss cannot count on Peeta's support, because he is being controlled by those who wish to kill Katniss, who is one of the great symbols of the revolution. Meanwhile, Katniss has the support of a large group and equipped with weapons and equipment they start the war that wants to overthrow the power of the capital and President Snow.