he first season of the police procedural drama NCIS was originally broadcast between September 23, 2003 and May 25, 2004, the first season essentially dealt with introducing the characters and their strengths, skills and weaknesses. It also introduced the main foe for the first two seasons, Ari Haswari, two recurring characters in the form of Timothy McGee and Jimmy Palmer after Gerald Jackson, Ducky's assistant, was shot, and Special Agent Caitlin Todd as Special Agent Vivian Blackadder's replacement.

Overview from themoviedb.org