Castle 8.3 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. Nathan Fillion / Stana Katic / Jon Huertas / Seamus Dever / Susan Sullivan / Molly C. Quinn / Tamala Jones / Penny Johnson Jerald / Ruben Santiago-Hudson Released (2009-) Seasons 8 seasons Status returning series Add to watch list