A prison transfer goes awry and Walt urgently pursues a serial killer and his fellow escapees, who have taken hostages, up a mountain. Facing an impending storm with very limited resources, Walt’s mettle is put to the test and hypothermic hallucinations force him to face his past.

When a teenage girl is found dead, Walt and the team investigate ties to the illegal sale of prescription drugs. Meanwhile Henry reconnects with an old flame and Cady returns home.

On election day, Walt and Branch aren't thinking about politics when Cady is badly injured by a hit-and-run driver. Vic and Ferg investigate, and Walt has a flashback to when Cady was a little girl.

Walt and Branch team up when an apparent suicide is connected to Cady's accident. Meanwhile, Detective Fales returns with warrants, forcing Walt and Henry to face what happened in Denver.