After budget cuts and personal demons forced him off the streets of San Pedro, Detective Nick Terry's beat became the classroom, where he patrols the minds of the people in his beloved hometown.

After a serial killer imitates the plots of his novels, successful mystery novelist Richard "Rick" Castle receives permission from the Mayor of New York City to tag along with an NYPD homicide investigation team for research purposes.

The close-knit Walker family deals with struggles and triumphs.