Stripped of his position as a general, Lucy will be imprisoned in the North Palace, serving the Crown Prince in bed. Though the Crown Prince pampered him, the man was a complete ass, leading to multiple misunderstandings. But Lucy had tolerated the Crown Prince many times because he loved him.
The last straw for Lucy was the Crown Prince's approaching wedding to Salena (NOT SURE IF I REMEMBERED THIS CORRECTLY, INCLUDING THE FEMALE's NAME) — this pushed Lucy to escape from the North Palace.
A friend came to save him. It was successful. However, during the escape, he had severely wounded the Crown Prince, marring their separation with regret and bitterness.
With Lucy's absence, the Crown Prince gradually realized his wrongdoings, and chased after Lucy. It took him several months of chasing before finally getting his chance to catch him.
It was when Lucy was chased by another enemy from a nearby country, and the Crown Prince managed to save him. At their reunion, the Crown Prince conveyed his apologies and confessed his love for Lucy.
More unnecessary scenarios and voila! Happy ending.
This summary sounds pretty calm and cliché, but in the novel, there was lots of angst, especially in the chasing parts.

...and your blood pressure will just doubled. Finished it anyway. Guess I'm sick in the head since I enjoy stories like this, the wife-chasing crematuriom vibe.