Paul is in his room sad because some boys bullied him by telling him that he was gay, his sister comes in and decides to give him advice, but the boy has no idea if he is gay or not, so he asks his sister for help, He advises this, but the boy wants to know for sure if he is gay or not, so he asks his sister to undress, she refuses at first, but little by little the situation will become more compromising for both of them. They are still virgins and very religious, which is why they cannot cross certain lines, but circumstances make this not possible. She begins to access more and more things until her brother by "accident" takes her virginity and thus proceeds an encounter full of anal sex, anal blowjobs, rain of urine and humiliations that will make them fall into sin, but will prove once and for all if the boy is gay or not.