Taken from ANN:

In the Kingdom of Wellber, Princess Rita is to be married to Prince Gernia of nearby Sangatras — a political marriage to prevent another war between the two countries. When the marriage plans go drastically awry, and Princess Rita is forced to flee the country on a mission to far-off Greedom, hoping to prevent the coming war, she finds a companion and friend in the cat burglar Tina, who has her own reasons for travelling to Greedom.