He was betrothed to the wrong sister
General Zahn was pleased that Emperor Blaze thought enough of him to arrange a marriage to his adopted daughter, London. Even though he really didn't feel anything for her, it was his duty to the crown. But London did not feel that way. She wasn't a piece of meat to be bartered. She ran away the first chance she got.
Using the DNA tracker, he thought he had found her. Gen. Zahn didn't understand the feeling he was having for his intended. She tried to tell him but he wouldn't listen. Zahn had his own method of punishing that made Paris not able to explain her situation. When she did, Zahn was ashamed of his behavior, but he knew deep down he couldn't marry London, not after being with Paris. Paris couldn't think of a future without Zahn. At least now Paris gets to see her long-lost mother, the Queen Calliope.
I really didn't care for this trope. The story ended too abruptly. Too much was left unsettled for me.