Dusk till Dawn

Desiri Academy is a school who invites many who are gifted, at least being rich will get you a place into this prep high school. But of course, every school has it's downs. The president and vice president are like sisters just without the same family. They talk the same, have the same personality, and can even unconsciously think the same things, as long as they are both awake.
But the two friends have made a system enough to corrupt the whole world. Gambling is the success to this school; they had got inspired by Hyakkou Prep. If you loose a gamble, you are considered a "cat" or a "dog", a house pet. People can control you however they like if you are a house pet, and oh boy it's worse if you loose to a student council member...
All of the student council well except the vice and the president are curious to how the girls ruling the school have the same minds, and are taking risk to find out why. So much risk... they will endure suffering.