In another world, beings known as ‘guardians’ live in harmony with humans. Since those who have the best guardians have the brightest futures, everyone wishes to have the best guardian. Yuuki doesn’t have any relatives, working part-time day and night just to make enough money to attend school. One day, a maid who called herself his imouto appeared before him and abducted him into a waiting private jet. There he was greeted by a stern-faced old man on the monitor, who revealed that Yuuki was actually the grandson of the head of the industry leader of the guardian industry, the Ootori Group. After the death of his son a few years ago, he wanted to pass on the Group to Yuuki, since he was the only remaining male relative. Yuuki was excited at his sudden good luck, however he was told that incompetence would not be tolerated. He was enrolled into the extremely famous guardian school Suzakukou to become a ‘guardian master’, but… isn’t this a girl’s school? Three girls Ouka, Itsuki and Neon all claimed to be his future wife, and they all ended up living together with him at the dormitory. The sharp-tongued imouto maid Aoi was also there, and she told him that in order not to disappoint his grandfather, he should win the school’s upcoming guardian tournament. [From Hau~ Omochikaeri!]