The show doesn’t focus solely on the crimes and investigations that take place in New York. The people who make up the lab team also have their own lives that develop over the run of the series. Members of the lab fall in and out of love with each other and citizens outside the police department. On a couple occasions, the past of one person or another comes back to haunt them and the team at large.
With the exception of time for a couple brief leaves of absence, Detective Mac Taylor leads the investigative team for all nine seasons of the series. Played by Gary Sinise, he is a former Marine who grew up in Chicago. His wife was killed in the September 11th attacks on the World Trade Center. Since then, he has dated and formed other relationships. However, his job remains his main focus and comes before a social life.
Another Detective on the team, Danny Messer, comes from a rough life associating with an arm of the Italian mob. He is played by actor Carmine Giovinazzo. Danny’s brother is later found dead while trying to protect the rest of the family from the actions of the mob. Danny meets another employee of the lab, Lindsay Monroe, and they develop a relationship. The two are eventually married and have a daughter together. They are threatened in their home by a fugitive Danny had faced down a number of times before. Lindsay is given a medal for shooting the man in their home to protect Danny and their daughter. The sixth season started with Danny in a wheelchair after a drive-by shooting injured him at the end of the fifth season. He continues to work in the lab while healing and gradually regaining his ability to walk.
Hill Harper plays an intelligent man who moves from the morgue to the lab. Sheldon Hawkes started in the Medical Examiner’s office after several years as a surgeon in the emergency room. His knowledge and talents are called upon in the lab, in the morgue and in the field. He is very capable at his job but doesn’t get promoted to the level of detective.
The liaison between the lab and police department is Detective Don Flack, performed by Eddie Cahill. He is from a long line of law enforcement employees. He is a good friend of Danny Messer and develops a relationship with lab technician Detective Jessica Angell. Unfortunately, Detective Angell is killed in the line of duty. This leads to a particularly rough period of time for Detective Flack.
Detective Stella Bonasera is the second-in-command of the lab under Detective Taylor. She grew up in foster care after some time in an orphanage. Her lack of a biological family leads her to adopt the lab team and use them to fill in the missing parts of her life. One case causes problems with connections to her Greek ancestry and one of her favorite professors. Stella left the team at the end of the sixth season when actress Melina Kanakaredes decided not to renew her contract.