The Secret of Light and Darkness

On his way to congratulate the city lord, Lord Li finds an abandoned baby by the roadside, with no idea who the child is. Six years later, the child awakens an astonishing talent! By day, he is the princess's death-sworn servant. In secret, he is an assassin. During a mission, he unexpectedly learns the secret of how to become immortal. What he never expected is that this secret is connected to his own origins.