The Crimson Labyrinth is the story of an elaborate role-playing-game in which a group of Japanese people are forced to participate. The story centers around the experiences of Fujiki in the game, beginning with him waking up in what turns out to be a desolate part of Australia. He has no idea where he is or how he get there, but he finds he has a 'pocket game machine' that offers some information- such as that he is in a game and that he must survive the labyrinth to win the prize money and be returned to earth.
Fujiki soon comes across another player, Ai, who seems as clueless as he is, and the head to the first 'checkpoint' where they meet the rest of the people who have inexplicably found themselves there. There are nine of them, and at this first checkpoint they must choose which direction to head in, each offering something different: food, information, survival items or self-defense items. The choices seem fairly straightforward, but turn out also not to be all they seem. Fujiki and Ai opt for the information, and for the rest of the game they do have an edge on everybody else as far as information goes; however, that can only help them so much.
It's soon very obvious that this is, as Fujiki says, a zero-sum game: for someone to win, someone else to lose. And it sure looks like surviving means that one has to be the last man (or woman) standing, leaving everyone appropriately suspicious of one another.
The machine Fujiki and Ai have, and the cassettes with additional information they pick up at various checkpoints, reveal more and more about the game and their situation. Soon enough, the game is one of hunter and hunted- and there is some decent tension here as they are on the run.