Glass Casa follows Jamie's bachelorette party as it takes a dark turn when an unexpected guest is found dead at their secluded hillside mansion. Deception and paranoia grip the group as they suspect each other. With no way to call for help, secrets unravel, and they uncover a sinister history. As threats escalate, they realize someone knows their dark secrets. Amid chaos, they turn on Jamie's fiancé, Alex, only to discover his motive for setting up the eerie house scares.