The White Cat's Revenge as Plotted from the Dragon King's Lap, (Light Novel) Vol. 8

Peace returns to the Imperial Nation, and Ruri Morikawa enjoys a quiet life with her partner, Jade, in the Nation of the Dragon King. But the tide suddenly turns when she receives a letter from her grandfather, Beryl, who has been journeying around the other world. Soon after, a plea for help arrives from the Beloved Celestine and Queen Padparadscha, who reveal that the Nation of the Beast King has fallen into enemy hands. Ruri must act fast, or the Beast King and everyone else in the country will be in mortal danger.