When Riley, who practiced an ingenious pyramid method of skimming numerous bank accounts for over half a million dollars, is strangled, exactly the same way -not revealed to the press- as Lisa Bayle, for whose murder Don Eppes' investigation once put Cliff Howard in jail after a plea bargain-confession, Don now fears the wrong man was arrested. Charlie helps him quantify the unlikeliness of a coincidence and seriously doubt the forensic evidence. Electrician Jose Salazar, whom Don suspects, still turns out to be innocent of Lisa's murder, but Charlie realizes that's not the point: what if a third person committed both murders, linked rather by the victims?

A prison transport bus crashes after maneuvers by two other vehicles, several inmates escape, including the dangerous McDowd. Charlie gets on well with CHP Officer Morris on the scene and works out mathematically it was no accident, both other drivers probably were in the game. Dad is worried Don might be returning to the period he regularly worked in fugitive retrieval, especially now a former colleague, burly federal marshal Cooper, is on the same case. After finding a lesser fugitive, Charlie's mathematical probabilities approach helps reconstructing the remarkable movements of McDowd in LA, which leads to a worrisome motive relating to a DEA case and likely further accomplices...