South Dakota,1999. A woman is found drowned in her bathtub. An autopsy shows a high level of the sleeping pill Temazepam in her bloodstream. It looks like a suicide that is, until investigators take a close look at her husband's computer. Turns out he's been researching painless killing methods on the Internet and taking notes on sleeping pills and household cleaners. Armed with that evidence, prosecutors are eventually able to put him behind bars.