Betrothed to his beloved, scholar Sung Yeol unexpectedly joins the undead. Now he must track down the one diary that will destroy Gwi, a bloodthirsty vampire determined to rule the human world.

In the midst of Sung Yeol's search for the lost diary, he discovers that the people are beginning to question the prince's death that took place a decade ago.

While Yang Sun insists on helping Sung Yeol track down the journal, Crown Prince Lee Yoon continues to hunt down all those who defy the crown.

The search for Forbidden Quest heats up, as talk of the sequel attracts more attention. With Prince Sadong's memorial approaching, living in hiding becomes more difficult for Gwi.

As Gwi continues to look for the manuscript, Sung Yeol struggles with how his growing feelings for Yang Sun strike his desire to live as a human.

Yang Sung is reluctant to leave when Sung Yeol sends her away. The king discovers the identity of Forbidden Quest.