This description is based on a message from Brent Nelson.
Call Partner is a Rook game for four players. All 57 cards are used, and the 1 is high in each color, so that the ranking order is 1-14-13-12-11-10-9-8-7-6-5-4-3-2. In the trump color the Rook card ranks between the 11 and the 10. The card values are:
So the total value of the cards in the deck is 180 points, which, together with the 20 points for winning the last trick, makes a total of 200 points at stake on each hand.
The players then bid to decide who will have a chance to choose trumps. Each bid is a positive number, which must be a multiple of 5. The dealer has the first chance to bid and the turn to speak passes clockwise around the table. At your turn, you can either bid or pass. Each bid must be higher than the last, and a player who has passed cannot bid again in that hand. The bidding continues as many times around the table as necessary until three players have passed. The fourth player is the high bidder, and the high bidder's team tries to take at least the number of points mentioned in the final bid.
The bidder then picks up the nest cards, without showing them to the other players, to make a hand of 18 cards, and then discards any five of these cards face-down to form a new nest. Having discarded, the bidder chooses trumps by naming a color, and also calls for a partner by naming a card. Whoever has the called card becomes the partner of the bidder. Those two players play together as a team for that hand only, and the other two players form a team playing against them. [The holder of the called card should not reveal who they are - their identity will become apparent when the called card is eventually played to a trick. If the bidder holds the called card, the bidder plays alone and the other three players form a team.]
The player to the left of the high bidder leads any card to the first trick. The other players in turn must play a card of the same color if they can. If they have no card of the led color, they may play any card. The Rook card counts as a card of the trump color. When everyone has played a card, the trick is won by the player of the highest trump, or, if no trump was played, by the highest card of the color that was led. The winner of a trick leads to the next. The winner of the last trick takes the cards which the bidder discarded into the nest.
At the end of the play, each team counts the total value of the cards they have won in tricks. Since the scores are accumulated from deal to deal but the partnerships can change for each deal, it is necessary to keep a separate score for each player. If the bidder's team took at least as many points as the bid, then each member of the bidding team scores the total amount of card points won by the team. If the bidder's team take fewer card points than the bid, they do not score anything for the cards they won; instead they subtract the amount of the bid from their previous score. The members of the non-bidding team always score the total number of points taken by their team, whether the bid was successful or not.
The game ends when a player or players reach 500 points or more. The player who then has the highest score is the winner.
*Information courtesy of John McLeod