The oceans have many tides, just as destiny and fate do. An astrologer reads the stars and prophesizes the end of the world to the King of Land. Sadly, the King passes away before he can address this matter. On his deathbed, he entrusts his eldest son, the Crown Prince of the land, with the task of preventing this calamity.
The Nation of Land, Oreios, the Kingdom of Oceans, Praedixit, and the Kingdom of Fire, Kansai, each possess a heart. The Heart of the Earth, Lapis, the Heart of the Ocean, Aqua, and the Heart of the Fire, Ignis, combine to create the venerable artifact capable of halting the impending disaster. However, each heart can only be found by those who resonate with it.
The Crown Prince, who resonates with the Heart of the Earth, embarks on a journey to fulfill his father's wish and save the world. Along the way, he encounters a young girl with no memory of her past, who knows only her name. As their paths intersect and become entwined, their destiny and fate collide like the tides of an ocean. Are they lovers or comrades? Friends or foes? Well, read to find out.