Ten years ago Satou witnessed Hime and her grandfather Alabaster teleport to Japan from another world. In the present Satou and Hime are best friends, though Satou has secretly fallen in love with Hime. However, he fears confessing his love as Hime possesses a wedding ring meant for her future husband. Hime abruptly reveals she is returning home. Unable to accept her absence Satou follows her to the teleportation circle where she reveals her real name is Princess Krystal of Light Kingdom and she is returning for an arranged marriage. Impulsively he follows her to the world of Arnalus and interrupts her wedding to Imperial Prince Marmarugius. The wedding is attacked by an Abyssal Demon seeking to assassinate Hime. Only Hime’s Ring of Light can defeat it, so she quickly saves Satou’s life by giving him the ring and a kiss. Marmarugius throws Satou a sword, causing him to instinctively slay the demon with Light magic. Satou is alarmed to learn he has unintentionally become Hime’s husband, Hero of Light and King of Light Kingdom. Despite the danger he decides to continue protecting Hime. Hime starts to develop her own feelings for Satou but reminds him their marriage is a formality so they will not be sharing a bed. More demons attack so Alabaster, revealed as Great Sage of the Light Kingdom, prepares Satou to fight once more.