Sam Swift, the former star of a hit cop series whose epic breakdown is broadcast to the public and sends her to rehab. Desperate to restart her career, she talks her way into shadowing lone-wolf private investigator Eddie Valetik as research for a potential comeback role. Though Eddie resents the babysitting gig, high-spirited Sam uses the skills she learned as an actor playing a cop and proves herself to be surprisingly valuable.

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.