Monster of the Week is a game run on the Powered by the Apocalypse game system.
It was notably used for the campaign Reckondary Characters, a sequel to Secondary Characters—which used the more socially-driven PbtA system Monsterhearts—bringing back the cast of the original campaign and placing them in a story with a heavier focus on combat. These campaigns took place in the CR era, but this system can also be used for games set in Quelmar's fantasy eras…such as A Long Night at Ravendean taking place in PR.