After the (somewhat NSFW) cutscene, the chapter proper starts with BJ underneath the resistance hideout, with the tunnel glider in the water. This is all part of Caroline's plan to ultimately hijack a U-Boat (while acquiring quite a bit of weaponry and ammunition in the meantime). The first thing is for the player to get in and drive the tunnel glider through the sewers. The initial objective is to navigate through the flooded sewers & other tunnels/spaces in order to get to the vast Berlin catacombs deep below the streets of Berlin. The catacombs is the Nazi's central munitions stockpile in Europe, and is considered the most secure site in Berlin. In order to get there, the player will occasionally have to dismount from the glider to clear or work around various obstacles such as gates. (Try not to lose track of the glider while you're doing this or you may lose your way back to it and run out of air!) For the last part of the route, you will have to abandon the tunnel glider altogether and alternatively swim and walk in order to get inside the weapons depot while dealing with more obstacles and at least one defensive trap.
Note: A number of Easter eggs and collectables can be found on or near your route.
Your next objective is to steal a fully loaded cargo train from the munitions stocks in one of the Depot's many underground marshalling areas. It arrives in from elsewhere in the depot just after you enter the depot and is carrying, as Caroline puts it 'Small arms, artillery shells, torpedoes and such for distribution to the Nazi war machine'. Expect heavy resistance in the marshalling yard if you chose a non-stealth approach, especially if you can't take down the yard's Commander quickly. As usual, the default security increases with the difficulty level.
- The catacombs would have been under the jurisdiction of the Wehrmachtsfürsorge- und versorgungsabteilung (basically the supplies directorate) of the Wehrwirtschaftsstab (War Economy Staff), which in turn was part of the Oberkommando der Wehrmacht (OKW) in other words the Wehrmacht High Command. In theory the general staff of the German military, in practice the OKW served as Adolf Hitler's personal military staff. The OKW has played a background role in some previous Wolfenstein games in the form of the Central Command/General Staff. Incidentally, the OKW plays more of a direct role in the sequel to the New Order, The New Colossus.
- Confusingly though, operational control over the catacombs would have exercised by the Heimatkriegsgebiet (HK) or Home Command of the Oberkommando des Heeres (OKH), i.e. the German Army High Command. The OKH was subordinate to the OKW (at least that was the idea!).
- The Tunnel glider is a one man Diver propulsion vehicle, in this case with a onboard breathing apparatus for its operator, reducing the need for him or her to wear full scuba gear. It would normally used by municipal maintenance personnel to reach otherwise inaccessible parts of the Berlin sewer system.