Confront the dark side of paramedic Paul Novak, who hid his deadly impulses beneath a veneer of heroism; explore the evidence that helped investigators determine that this manipulative, unfaithful man brutally murdered his estranged wife, Catherine.

Malcolm Webster's wife, Claire, died in a car crash in a remote part of Scotland; his second wife Felicity almost dies in similar circumstances in New Zealand.

Kathy Augustine was a politician serving in the Nevada Senate; shortly after her husband of 17 years dies from complications of a stroke, she marries Chaz Higgs, a critical care nurse whom she met while he was caring for her late husband.

Suspicion builds as the DaVita dialysis center in Texas experiences a huge increase in code blues, with many patients succumbing to their injuries.

William George Davis, a nurse in Tyler, Texas, was just 32 when he began a reign of terror over patients recovering from heart surgery; prosecutors claimed that Davis had at least eleven victims, of whom seven died.

After Eric Lloyd's wife claims his death was due to natural causes, Marie Whiston, who had been looking after him between nursing shifts, becomes anxious to attribute his demise to ill health.