The ABC police drama "The Rookie" written by Alexi Hawley and directed by Liz Friedlander was previously booked as a series, starring Nathan Fillion, the male lead of "Castle". "The Rookie" is adapted from a true story. Nathan Fillion plays the protagonist John Nolan, who is the oldest rookie police officer in the Los Angeles Police Department. John left his comfortable small town and came to Los Angeles to pursue his dream of being a police officer. At this moment, the other rookies around him are in their early twenties. They are considered by their superiors to be the protagonists who are just experiencing a mid-life crisis and have to deal with this dangerous, funny and unpredictable world like their younger companions. Melissa O'Neil, the star of "Dark Matter", plays the female protagonist-Lucy Chen, a rookie police officer in Los Angeles, and will have a relationship with John. Afton Williamson plays Talia Bishop, who has just been promoted to a training officer. The first person assigned to her for training is rookie John. Eric Winter plays the aggressive training officer Tim Bradford. Richard T. Jones plays Sheriff Wade Grey. As a supervisory officer of the police department, he and John become sworn enemies. Titus Makin plays the enthusiastic rookie Jackson West, whose father is a senior commander of the Los Angeles Police Department. Alyssa Diaz plays Angela, a training officer who hopes to become a detective, but it becomes a problem when Jackson West is assigned to her because his father has a say in the police department. Mercedes Mason plays Superintendent Zoe Andersen, the protagonist's confident and rude commanding officer.