'Arthurian Ghost Knights is a game of conflict for Stonehenge: An Anthology Board Game. The players represent deceased Arthurian knights, fighting evil spirits for glory at Stonehenge. Each turn, you draw a card, then play a card from your hand. If it's your color, you simply place one of your guards at any trilithon. If it's an opponent's color, you place one of her guards at a trilithon, and gain glory for "helping" her, and get to place a sword (bar) on the altar stone. If it's black, it's Morgan Le Fay's, and you may do either, but getting no reward for "helping" an opponent.
Four times during the game - two random times in the first half, two random times in the second half - there will be a struggle round followed by a scoring round. During the struggle round, you use the swords you have on the altar stone, each coupled with a card, to forcibly alter the situation at the trilithons, jockeying for positions that will gain you the most glory: If you play a card of your color, you add one of your guards to any trilithon. Playing a card of an opponent's color lets you remove one of her guards from any trilithon. Playing a black card (Morgan Le Fay) lets you do either.
When the struggle is done, the scoring occurs. At each trilithon, the player with a plurality of guards gets one glory for each guard she has there - double if you're alone there. In a tie, everyone gets their respective glory there. If you have a guard at each of the five trilithons, you get 5 glory.
After the fourth scoring round (or someone gets lapped!), the game is over. The player with the most glory wins! (There are a couple of tie-breakers.)
Arthurian Ghost Knights is an official game for Stonehenge: An Anthology Board Game.