Protocol Squared Presents: House of Keys - Iron Medusa (2019)

From publisher blurb:

House of Keys is a story roleplaying game about confusion and misdirection. Set inside an enigmatic mansion, riddled with cryptic messages, the game tells the story of fantasy adventurers unable to escape a trap laid centuries ago by unseen forces. Characters are adventurers at the end of a quest unable to escape a house of apparitions, dead-ends, eerie sounds, locked rooms, puzzles, and shifting corridors. How will they escape when all hope seems lost?

House of Keys draws upon the lore of the Iron Medusa game series, of which this is the first game. Set in the Slavic-inspired fantasy world of Ducrisa, each game explores a unique part of the setting. In this particular instance, an abandoned mansion draws the characters into a trap they may never escape from, as magical forces and spirits pin the player characters into an ever-shrinking (metaphorical) noose.

Each game in the Protocol Squared series includes rules for set-up and play for 4 or more players (though 3 is possible, just not recommended). This is the next step in the Protocol game series, involving more details, world information, character classes, and so on. This document includes 15 classes, numerous backgrounds, and 30 pages of world information.