P.I.是一个纯粹的扣除游戏，玩家在连续三次的迷你游戏中竞争，以便看到谁在解决他们的情况下获得了最好的排骨。
每个迷你游戏都是一样的。开始时，你会收到秘密的一张可疑卡（12张），一张犯罪卡（10张）和一张位置卡（14张）。这组信息表示你左边的玩家必须解决的情况。游戏板显示十四个位置，使每个位置触及其他位置;每个位置都有可疑和犯罪砖的空间。洗牌嫌疑砖（12，加两个“不可疑”）和犯罪砖（10，加四“无犯罪”），然后将一个面朝上放在每个位置。每个嫌疑犯，犯罪和地点都包括在一张证据卡中，并显示了9张证据卡。转牌后，玩家可以放置调查员，选择证明卡或尝试解决她的情况。当您将某位调查员放置在某个位置时，右边的玩家会看到他的手提卡，然后在这个空间放置一张光盘，用于他所持有的与这个空间中的嫌疑犯，犯罪或位置相匹配的个案卡。此外，他在每个嫌疑犯，犯罪或与此空间相邻的地点，在这个空间上放置一个立方体。
当您选择证明卡时，右边的玩家将光盘放在匹配的瓦片上，如果该卡匹配他所持有的一张卡片，将一块立方体放置在匹配的瓦片上，如果该瓦片与匹配其中一张卡片的瓦片相邻，或者如果您做出了野蛮的猜测，则不会放置任何内容瓦片不与任何东西相邻。
为了尝试解决这个问题，你在你的猜测上放置一个黑色的标记。如果错了，你会受到两点惩罚，继续下一回合。如果是的话，你会收到7,5,3或1分，取决于有多少人在早期的回合中解决了他们的情况。
一旦所有人解决了他们的案件，只有一个案件仍然存在未解。所有使用过的调查员都从播放中删除，然后重新设置板卡和下一个小型的卡片。每个玩家总共只有五名调查员，所以明智地使用它们！
三个迷你案件赢得了最多的分数。
P.I. is a pure deduction game, with players competing in three consecutive mini-games in order to see who's got the best chops in terms of solving their cases. Each mini-game plays out the same way. To start, you receive in secret one suspect card (out of 12), one crime card (out of 10), and one location card (out of 14); this set of information represents the case that the player to your left must solve. The game board shows fourteen locations arranged so that each location touches a few others; each location has space for a suspect and crime tile. Shuffle the suspect tiles (12, plus two "no suspect") and the crime tiles (10, plus four "no crime"), then place one face up in each location. Each suspect, crime and location is included in a deck of evidence cards, and nine evidence cards are revealed. On a turn, a player either places an investigator, chooses an evidence card, or attempts to solve her case. When you place an investigator in a location, the player to your right looks at his case cards, then places a disc on this space for each case card he holds that matches the suspect, crime or location in this space. Additionally, he places a cube on this space for each suspect, crime or location that's adjacent to this space. When you choose an evidence card, the player to your right places a disc on the matching tile if the card matches one of the case cards he holds, places a cube on the matching tile if this tile is adjacent to a tile matching one of the case cards he holds, or places nothing if you've made a wild-eyed guess and the tile isn't adjacent to anything. To attempt to solve the case, you place a black token on your guesses. If wrong, you're penalized two points and continue play next turn. If right, you receive 7, 5, 3 or 1 points depending on how many others have solved their cases in earlier rounds. The mini-game ends once everyone has solved their case or only one case remains unsolved. All used investigators are removed from play, then the board and cards are reset for the next mini-case. Each player has only five investigators total, so use them wisely! Whoever has the most points after three mini-cases wins.
