Jin Yu decides to return to the wolf pack after being rejected by Meng Jiu and runs away, leaving a letter for HQB at his estate. His servants deliver it immediately to him and he rushes off in a rage saying that chasing after thousands of Xiong Nu people wasn't hard for him, so chasing after one JY won't be hard for him. There is no such thing as giving up in his book and HQB was going to win her.
JY traveled with a caravan into the desert. At this time, Meng Jiu's men were looking for her as well, tracking down every caravan that had left the city. When they reached a rest stop, JY decides to wash up for the next day's journey, but HQB barges in as she's bathing. She argues with him about seeing her in her undressed state and all he wants to do is to whisk her away, so she calls for help saying there's a thief. HQB proceeds to wrap her in a towel and steal out the window with her over his shoulder. He puts her on his horse where he takes her off to the army and dresses her like a man, and they share the same tent until they return to the capital many months later. And inevitably, stuff happens
and she agrees to marry him.
One of my favorite parts of the book is when they attack Xiong Nu and our adorable HQB/JY couple decides to masquerade into the Xiong Nu camps after the battle for a little fun and meet up with JY's long-time nemesis, Yi Zhi Xie. There's an arrow shooting competition, an almost death, a flight for their life, and JY's sudden and deep realization that she loves HQB. If you want to hear about that too, I can give you a quick summary
I don't know if that would belong in the novel spoiler thread though