Mizuki Kouichi is about to take his final exams and graduate from high school when he suddenly finds himself transported to a fantasy world-specifically, to a kingdom of titans! The country's beautiful denizens are almost twice the size of Kouichi, who was a tall basketball star back home. To his surprise, one of the giants, Prince Caius, claims Kouichi as his bride! Due to a dire prophecy, the prince's upcoming nuptials cannot be with anyone of his world, so he's happy to take Kouichi as his 'wife.' What starts as big trouble for Kouichi turns into a grand romantic adventure when he finds out that Caius truly has a lot of love to give.