What does it take for a decent man to turn into a killer? Greg, a married man, has been having an affair for three years with another man's wife. One evening, after a fight with her at their rented love nest, he storms out. When he returns an hour later she is dead. Did he kill her in a fit of rage and blank it out, or did someone else do it while he was out of the building? 
Roy Grace faces his most mysterious case yet.