I've Been Looking for So Long. I Really Want to Read One Again. Please! 找了好久，真的很想再看，求求了

Are there any quick transmigration stories where the male lead is a crown prince of a fallen kingdom? He hides his identity and plans to return for revenge. He’s been poisoned by a Gu, so the female lead gives him a blood transfusion. But at first, he only cares about revenge and treats her coldly. Heartbroken, she leaves as soon as the transfusion is done.