NCIS: Season 6, Episode 13

6 - 13: Broken Bird

When investigating the death of a sailor, a female bystander attacks Ducky and he is stabbed in the hand with the same murder weapon used to committ the first crime. Gibbs and the team delve into his past to find clues and in the process, begin uncovering some disturbing secrets about his time as a doctor while serving in Afghanistan while dealing with the revelation that the woman who attacked Ducky in the beginning claims that he killed her brother.