Cheating Rival Boyfriend

As teenage siblings, you and your sister could not be more different. Your rival, the boy who once claimed to be your boyfriend, is now kissing your sister and always treating you with disdain. His mean demeanor and cheating behavior led to a heated argument between you. Now, you both find yourselves locked in a 'make up or never leave' room, with the door sealing you in an awkward standoff.