Detective Archie Sheridan just has to get through the next few days, then his birthday and Halloween will be over. But with escaped serial killer Gretchen Lowell on the loose, the investigation into the murder of a DEA agent demanding his attention, and journalist Susan Ward showing up at his apartment needing a favour, it's going to be a long weekend.

Soon Archie finds himself crashing a masked ball on a private island owned by Jack Reynolds, a notorious local drug kingpin. By morning, Archie is back on pain killers, a guest is dead and Archie quickly realizes that little is what it seems. One thing is clear: Gretchen is back, and Archie's nemesis and sometimes lover has something special in mind for the birthday boy, something she's been planning for a long, long time. On Halloween Eve, with time running out, and the life of someone close to Archie on the line, Archie knows his only chance is to give Gretchen exactly what she wants. But Gretchen will prove more horrifying, and unpredictable, than Archie could ever imagine...