The Shadow Veil wants to cover the land with darkness, so your challenge in The Four Doors is to collect the relic from behind each door, then gather everyone at the beacon in order to light it.

On a turn, a player takes up to three actions: drawing a card, moving to an adjacent door, giving a card (or relic) to someone at your door, illuminating a shadow card from your door by discarding a card that bears a lantern of the same color, or finding a relic by discarding four cards of the color matching your door. Each adventurer has a special power that modifies an action or offers a new action.

Each door has a relic behind it, and once you find a relic, the holder can use its power by discarding a card bearing the relic's symbol, sometimes as an action on its own, sometimes not.

To end a player's turn, they draw two cards, then place "shadows" from the deck equal to the shadow level. If a fourth card would be placed on either side of a door, flip the card to its partially closed side; if the door would flip a second time, remove it from play. If the players don't already have this relic, they lose.

Each time players need to shuffle the deck, the shadow level increases — and this level will increase more quickly as the game progresses since some cards, such as spells that provide a one-time effect, are removed from play instead of being discarded. If you have no cards to shuffle or the shadow level tops out, the players lose.