Valerie accidentally forms a bond with Maxwell, a light demon, and begins seeing the dangerous supernatural world hidden around her. As the two constantly bicker yet protect each other, Valerie gradually discovers her own light-based powers and confronts many dark forces, including a serial kidnapper, the dark demon Zane, and other malevolent entities. Maxwell, haunted by the death of his former lover Juliana, repeatedly tries to distance himself from Valerie to keep her safe, causing both of them pain. Yet every time Valerie is in danger, Maxwell returns to save her, and their feelings grow deeper. The climax comes when they face Mason, a fire demon who hunts human–demon couples; Valerie risks her life in battle while Maxwell nearly collapses from exhaustion. In the end, Mason is destroyed, the threats fade away, and Valerie and Maxwell can finally stay together in peace.