Jenseits der Schwelle (2005)

"Jenseits der Schwelle"("Beyond the Threshold") is a publication in the series "Cthuloide Welten Bibliothek", which is an offspring of the german "Cthuloide Welten" magazine published by Pegasus Spiele, containing four scenarios for the 1920s, taking place in Germany, Great Britain, USA and Transsylvania.

From the publishers website (translated):

"Liquid Darkness"
by Sebastian Weitkamp
Burglary in the Prussian State library in Berlin! But the thief hasn't come far, to be exact: he's standing apathically in a closet. The characters start their investigations and follow a trail to Gdansk. How is the sanitarium of Dr. Dryander connected to this case, and what secret of ancient times is hidden in the ruins of a crusader's castle?
A mysterious adventure in Germany in the 1920s.

"The Lord of the Winds"
by Günther Dambachmair
On a body the investigators find an ancient bronze bracelet, which starts a series of events into which they are torn very quickly. A group of sinister people in black robes is on their heels, and only Prof. J.R.R. Tolkien himself is able to help them.
A fast-paced adventure in 1920s Great Britain.

"The Plantation"
by Wesley Martin
In the southern states of the US there are extensiv and malicious swamps, and the people living in this isolation have preserved archaic rites and traditions. Yig, the Snake God, is worshiped and the investigators should follow their investigations regarding a disappeared young colored boy discreetly. But soon they'll find themselves in a life-threatening situation.
A dangerous adventure in 1920s USA:

"The Castle in the Mountains"
by Jan Christoph Steines
An alarmingly real apparition of ancient soldiers and the blooming of a long faded tattoo make an investigators explore his family's history. The clues lead to Transsylvania, where a Count in his castle in the moutains is already waiting for him and his friends.
A horrifiying adventure in 1920s USA and Transsylvania.