The scene starts when a HCL container falls down and the people arranging the container suddenly seas a body already eaten up by the chemical inside the container.

As Kate, Gibbs and Dinozo were leaving the office, Kate spills over the coffee of Gibbs and Dinozo warns they are in unchartered territory.

In the scene McGee makes his first appearance and Gibbs acknowledges by pulling a brief case under his seat.

In the investigation, they figured out that the officer was put in the acid to make sure the body could not be identified and since the submarine had complete attendance, the killer took his identity.

Before going to the sub, McGee warns Gibbs that the chief of the sub was difficult and Gibbs moves close to the face of McGee asking him if he thought Gibbs was not difficult. Classic Gibbs.

Victorian England? That is what Kate says when the chief of sub didn't want a female on the sub. Gibbs handles that and Kate experienced her first submarine ride aboard Philadelphia. Kate says it looks better that the airplane moving from 120++ knots to 0 and vice-versa.

As Gibbs and Kate are aboard the sub, they would have to interview five new crew members who might have taken the identity of the killed man. NCIS will have to wait since Philadelphia has ASW (anti-submarine warfare) exercise against Augusta.

NCIS have interviewed the five new crew members but nothing came up. Back in the lab, Abby was able to re-construct the face. McGee is with Dinozzo and he asks whether Abby was cute after she sent the image to them. Dinozzo let out a big smile and told McGee not to talk about it again.

Since they could not match the five new crew members, NCIS figures out that there was an accomplice in the records section and switched the records. McGee and Dinozo follows up and it turns out there were so many employees handling records and would not be able to trace who worked on the records of the new crew members. McGee asked one brilliant question whether someone resigned in the last few days and it happens that one resigned two days ago. They quickly closed in on the suspect and found traces of evidence that suggest the submarine was being targeted with a serum has to be released in the sub.

NCIS founds out about the suspect who just killed himself when he realized they have surfaced and they are on to him. But it was just a backup because SOP says that dead bodies should be put in the fridge and the cold actually triggers the canister.