Dong Gong Jie Xia Qiu

After his country's destruction, a former monarch was captured by the enemy's crown prince and taken to the Eastern Palace. The prince, instead of executing him, decided to keep him as a prisoner under his control. Though the monarch expected only hardship, he finds that despite the prince's frequent angry outbursts, he is also granted unusual leniency and comforts. The monarch is puzzled by the prince's cryptic references to a shared past, though he cannot remember any events that might explain the connection.