It's Sally's birthday, but she and Mac are in no mood to celebrate as someone has broken into their house and stolen all the sharp objects (knives, scissors, razor blades and even Sally's knitting needles). Making things worse is that a serial killer known as the Asylum Killer is on the loose and he has written a letter promising a double murder for his next crime. The couple make the best of it despite their fears and try to celebrate. However, after drinking drugged champagne they are knocked unconscious and awake to find their house covered with a fumigation tent ...