This scenario puts the PCs out to see, guarding a mysterious package on a convoy, amid the news that the Nazis have another new trick up their sleeve, some kind of aquatic attack force. Though it is only mentioned as a possibility, if you're running the scenario, the PCs will encounter the new bad guys.
This Battlescene entry is pretty robust, providing a new heroic NPC as well as a few new NPC statblocks. The scenario is easily expanded to switch from merely having the PCs hold off the convoy attack, to allowing the PCs to find the undersea base that the Nazis have launched from and try to take it out.
Plenty of bang for your, literal, buck with this one as Vigilance Press continues to impress with their WWII entries for ICONS.