Rena and Taichi are usually just normal siblings who get along well... but they have a secret. They were tempted and once they had sex, they discovered that they have excellent chemistry, and they've become a brother and sister who will have sex the moment they're alone! Even after a friendly chat with their parents during a family get-together, they immediately have sex the moment they're alone! Their chemistry is so perfect that once they get turned on, they can't stop! Their orgasmic sex is always full throttle!