Because of the time travel in one of the movies, there should be some kind of order to these for it to make sense. So the plot from Frankenstein’s Army would be the first part. This would probably be followed by The 25th Reich, and finally Nazis at the Center of the Earth.
In this movie, a WWII team ends up in the Philippines behind enemy lines, carrying a device with them that they were ordered to carry. One of their members is the only person that knows of the true nature of this device. They eventually reach a point on the island where the expert says they can engage the device and it turns out to be a time travel device that takes them to the distant near a UFO crash. The expert betrays them, turning out to be a Nazi spy, and steals tech from the UFO and goes back to the future but not before damaging the device.
The team attempts to repair the device, engages it and arrives in the far future where the Reich has taken over the world with a huge fleet of UFO-like ships. The movie ends there, implying there will be more.
Part 2 – Inspired by The 25th Reich
BASICS:
What I like about my idea is that it starts in World War I and then we time travel to World War II (eventually).
The players are now in a different part of the world and a different time. Their cold weather gear is not needed. It’s tropical. Very Tropical. They can’t really tell where they are at.
Their mission has not changed – track down this mad scientist.
(I think this adventure should start out in the distant past in one of the dinosaur eras – perhaps Jurassic. )
PUSH
They have arrived in the distant past. Encounters with giant bugs, dinosaurs and anything else imaginative could happen.
They catch the trail of Dr Falkenstein and follow him. Once he knows he is being followed, he can start laying traps.
Dr Falkenstein gets to the UFO, awakens or attracts something to cover his trail and distract the players and uses the time gate in the UFO to go to his next stop – WW2. The players only have a short window to go through the time gate.
PULL:
The Time gate drops them close to the ruins of the castle (from part 1), in the middle of Nazi Germany/Austria. Whether through the actions of the doctor or the players, the church facility was destroyed. The players won’t know they are in WW2 but will find out soon when planes fly over or tanks drive by.
The mission remains – Get Dr. Falkenstein. The trail leads to his new lab where he is working other projects using tech from the UFO. In the chase, they face new enemies and weapons.
GIMMICK
in this timeline, Dr. Falkenstein has advanced his experiments with more modern technology and tech from the UFO. The player should face more new constructs.
In the movie, they faced robotic spider creatures that had human brains – at attempt at immortality.
Dr. Falkenstein will eventually escape to another time – the future – around modern day.
ENIGMA
One interesting idea I came up with was whatever the doctor was “recycling” the dead from WWI to help in WWII. His experiments really lead to how to preserve human brains in technological constructs.