When an unthinkably violent criminal flees before his trial, John Walsh joins local authorities on the chase for Michael Waguespack; Cal uncovers hidden and painful truths in a Christmas Eve tragedy that sent police hunting for Miguel Angel Martinez.

John and investigators follow the trail of a chilling 911 confession that leads them to dangerous Nimrod Guerrero; when Frederick McCaskill leaves a survivor clinging to life, police and Cal work to make sure this criminal doesn't elude justice.