"So, why the hell are we having a party in a killer's penthouse?!"
Lydia is a young woman who, infatuated with the rumor of a mysterious killer, takes this fictional man's place and becomes the Phantom Killer of the Penthouse. No matter how many warning signs she paints on the outside, people cannot stop breaking into her home for the thrill of meeting a masked murderer.
One day, a group of girls attempts to break in to set up a party. Lydia, both curious as to where the night can go and somewhat in love with these girls, pretends to be another party-goer and lets them take up space in her penthouse. How will she charm one of these girls while killing off their friends?