A chilling tale of toxic family dynamics and a sinister plot unfolds in "Killer Prom", where a devastating loss sets off a chain reaction of deceit and destruction. After losing her mother in an accident, a teenager's life becomes increasingly complicated when her father brings home a distant cousin with a dark secret: Sienna, a psychopathic mastermind hell-bent on recreating the prom she never experienced. As tensions escalate, the fragile bonds between family members begin to fray, threatening to unleash a deadly reckoning.