NCIS Office of Special Projects is sited in Los Angeles. They go undercover very intensely to seize felons that are a risk to national security because they have information on recent technological developments.
It all adds up to an hour of decent entertainment, and there's room for enough character development to give NCIS: Los Angeles a personality of its own.
It's all about the energized action, the cool tech and the momentum, all of which made this a top ten show and the number two rated scripted drama in TV (right behind the original NCIS) in its debut season.