While previous expansions have given players more cards and special abilities, MADNESS focuses on the social in social deduction. Madness replaces the regular Bite cards with a deck of psychosis-spreading bites. Wolves and humans can observe the spread of the madness to deduce who is on their team. Madness is contagious....
PLAGUES Plagues adds 10 new spells and replaces Night and Final Night cards with 12 apocalyptic Plague cards. Plagues trigger awful ongoing repercussions for the players accused of the most heresy. On your turn you may give a Plague token to a player you suspect is not on your team. When a Plague Night is revealed, everyone flips over unrevealed tokens and the player or players who have the most heresy become victims of the plague! Depending on the plague, the "heretic" players gain new, tougher, victory conditions. Some plagues can even turn the heretics into a new faction!
—description from the publisher