Origins showrunners david j. North and gina lucita monreal explain how the prequel series will be a darker story compared to the main series. learn more about the full cast of ncis with news, photos, videos and more at tv guide Leroy jethro gibbs (24 episodes) sean murray. Timothy mcgee (24 episodes) michael weatherly. Tony dinozzo (24 episodes) brian dietzen. A murder prompts the reopening of one of tony's old investigations, leading gibbs and dinozzo to reverse roles to solve the case.
