Wendy loves her husband, he's her best friend and soul mate.
But their sex-life leaves a lot to be desired, at least for Wendy it does. And that's where the problem sits - Dave, her husband, is happy with their 'wham bam thank you Ma'am' sessions. Wendy needs more and resorts to self-pleasure to satisfy herself and stop her from taking the more drastic step of having an affair.
So, when Wendy acts to save their marriage and suggests that they visit a marriage guidance counsellor to address these issues, Dave reacts with anger and hurt-pride but eventually comes round to the idea.
Their first session with Jack Danvers, Marriage Counsellor is acrimonious and ends unusually, with Jack suggesting that he sees them separately in future.
What neither of them realise is that Jack has taken an unhealthy interest in Wendy, one that he will stop at nothing to see fulfilled as he embarks on his latest 'special' project.
From bugging and stalking Wendy, though separate counselling sessions, and insidious seduction attempts - Jack tries every trick in his extensive repertoire to bed his target.
But, when Wendy spurns his advance, Jack loses his grip on reality and the stakes turn deadly as he takes extreme and violent measures.
Wendy and Dave must re-unite and fight for both their marriage and their lives in the brutal climax to 'Fatal Guidance'.