War begins to brew between the human survivors of a deadly plague and a thriving society of genetically evolved apes led by the sage simian Caesar. When their fragile truce collapses, the fight to become the dominant species starts.
The team travels to Detroit to catch a killer who, for the past three years, strikes on "Devil's Night," the city's pre-Halloween ritual.
In the sixth-season opener, Castle and Beckett deal with the fallout from their personal choices as a high-stakes investigation unfolds.
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