Losing Face

Plot
A necklace bomb explodes, killing a man and a good friend of Horatio's. With his friend (and mentor) gone, Horatio works doubly hard in this case, worrying Megan, who lost her husband in the line of duty. With three more bombs, they are put to the test to find out who is doing it and who are the targets. With evidence in hand, they search a Colombian port and discover things about the workers that they think will help the case. However, new evidence suggests that the bomber is after the bomb squad.

Trivia

 * Horatio is established to have been a member of the Miami Bomb Squad. The skills he learned there, would come up in many episodes throughout the shows run.