This is the story of Ryo, who was reincarnated in the world of swords and magic. It is a story of the royal road to survive using the magic of water attribute. What is magic? What is swordsmanship? How does it relate to the laws of physics that we know? Or what is politics? What is a nation? Why are there many 『kingdoms』 in reincarnation stories? Will republics not work? Can it be written …? Since it is a water-based magician, so it shall start with 『Hydrogen bond』!