Will and Jeff are half-brothers who have recently gotten back in touch with each other, and the relationship between them is uneasy at best. They are at the bar The Wild Zone with their friend Tom when they see a lone woman drinking at a table. They make a bet as to which one can chat her up and take her home. This is despite the fact that Jeff is in a relationship with Wild Zone bartender Kristin and Tom is married - albeit unhappily - to Elaine. The woman - Suzy - winds up picking Will, much to shock and anger of both Jeff and Tom. They don't go home together, but none of the men can get Suzy off their minds.
Jeff and Kristin have an open relationship, but Jeff's fascination with Suzy starts to come between them. Will has feelings for Suzy, but likes Kristin a lot and doesn't appreciate the way Jeff treats her. Tom's marriage with Elaine begins to fracture and he slowly loses his grip on reality. As for Suzy, she is married to a controlling, abusive husband, and having three guys so interested in her is not making life with her husband any easier. Their lives are destined to collide in unpredictable and violent ways.
As you might be able to tell from the plot description, The Wild Zone is more soap opera than it is a crime novel or thriller. As it is, it falls into that increasingly frequent - and annoying - category of a melodrama with a little bit of random murder thrown in to pass it off as a suspense novel. Admittedly there was some suspense, mainly in waiting to see how badly Tom would psychologically fall apart, but for the most part, this story went nowhere fast. The characters are very well-drawn, however, and that went a considerable way in keeping me involved in the story.
It finishes off with an absurd twist. While you can tell the author didn't simply pull it out of her hat, it didn't make it any easier to swallow. It meant that certain characters would have practically had to have been psychic to know that everybody would do what they did when they did it. Very silly. It did little to justify the slow, measured build-up that came before it.