Iris, the "Wise Princess Who Never Smiles," has just remembered her past life as Fiona, Warrior Princess from the neighboring kingdom. In this lifetime, however, the events that lead to Fiona's death have yet to happen, and Iris becomes determined to use the knowledge from her reincarnation to stop the person she suspects is behind her murder: Fiona's cousin, Prince Alvin.

In disguise, Iris moves to the neighboring country and becomes the princess' educator. But when she meets Prince Al, he turns out to be a cool-headed flirt, who, most-shockingly of all, is actually very sweet with Fiona... Can Iris figure out the truth in time to save Fiona from her fate?