Episode 5: Namesake.
Song during the cold opening sounds like The Vines. A couple oddities early on. First, after the credits, they're already at the crime scene. They don't do this often. No banter at the office, no "grab your gear". Then, Abby doesn't explain her findings in her lab, she goes upstairs to the squad room.
Anyway, the case seemed to take a back seat to the character development, which is something they do occasionally. As far as I remember, this is the first time we ever hear what happened to Gibbs' mom, even in passing. What I liked about it most, is that Gibbs seemed to shy away from his usual emotionless stoic self. I don't know if he's actually being able to share feelings, or if he only did it because of a war hero who needed his medal, but given the situation, I think it could have been both.
Oh, and McGee still has a cold. What is wrong with his voice?