After the tragedy of the Zodiac War, the government has put a new law in order. The twelve zodiac signs are to be separated, leaving families and couples split apart. Everyone has gotten used to it by now; the signs have even developed a mating pattern to ensure their children remain with them. But every fifteen years, the government hosts a lottery--for lack of a much better term--where twelve "lucky" young adults win the chance to intermingle. The government hopes for only one thing to come out of this: the zodiacs to fall in love with their compatible signs and produce a member of what they have dubbed the "superior race" which are then raised into being perfect soldiers. But the members of the house don't know. All they know is when people go into that house, they never come back.