Born as the illegitimate daughter of the king, Rein lived quietly in the royal palace as someone “invisible” to all. One day, a major conflict breaks out at the border, and she is sent to the Dragonkin Kingdom as a false princess—a political hostage. Trembling with fear, Rein arrives in the neighboring land, where she is unexpectedly welcomed with warmth by the dragonfolk, including the Prime Minister Sigurd. As she spends time among them, she finds herself drawn to Sigurd’s genuine kindness… But unbeknownst to her, he is the very man her father ordered to assassinate! A forbidden, pure love story between the “invisible” princess and the dragon prime minister!