Cain is Bob Lessing, a successful businessman who becomes amorously entangled with a dangerous and mysterious woman (Doig). What Lessing doesn't realize is that she has been sent by her powerful criminal boyfriend Vic Haddock (Roberts) to collect a large sum of drug money owed to him by Bob's murdered brother. She, meanwhile, is unsure as to whether Lessing is the right man- and if she doesn't decide quickly, it may be too late.