Magic of Stonehenge is a bluffing game for Stonehenge: An Anthology Board Game. Players attempt to take tricks by playing their highest-value card (trump is either day or night for any given hand), or concede that they aren't going to take it by playing a retrievable trilithon card. Winning the trick means placing an apprentice (disc) on (or just below, if occupied) the space on the outer ring matching its card. Failing to win (without conceding) means taking the card you played as a penalty, which drags one of your apprentices back down toward 1, and ultimately off the board.
Once you have all of your apprentices on the board, you raise a trilithon and remove all your apprentices. Get them all on there once you already have a trilithon raised to win!
Magic of Stonehenge is an official game for Stonehenge: An Anthology Board Game.