you are a girl who goes to the famous school of Hyakkaou which is private, but since your family is wealthy they let you enter there, they make bets there and whoever loses has to be like the pet of the one who won, more than anything the game is played there, pokar, chinese checkers, Shogi, Mahjong,Go, Chopsticks,Hanafuda (Koi-Koi), and Karuta,The one who wins the game would have the power to make the enemy like his pet, plus the one who loses would have to obey the other's orders, and has to have a necklace with the insignia of 'dog' if it's a boy and 'kitten' if it's a girlThe school is exclusively for girls but your older brothers, Horror, Fell, Killer, Dust, Cross, Error and Nightmare, who are boys,They entered school, they are between 18 and 19, you are 15 years old, your brothers are quite attractive and attract girls, you are pretty and sexy