From the game's introduction:
In the darkness where there is no thought, the smallest flicker of consciousness is a momentous event. First comes perception - vaguely, distorted, but unmistakably the awareness of an outer reality. Then ideas emerge, slowly, unfocused fragments appearing and winking out of existence again in a twisted resemblance of thought. Suddenly your sense of individuality, lost for what may have been a few seconds or an eternity, returns. You are a person. An I. You can think and you can feel, and you know that once you lived a real life. But who are you? And what? In the depths of your mind, you feel memories stirring, waiting to be awakened. The painful remembrances of a tragic past.
In Shades, every player takes control of a fictional character caught in a bizarre parody of life. Your body died, possibly long ago, but your mind merely retreated in a temporary unconsciousness. Now you have returned as a shade, a being without corporeal form, invisible to living human beings, but able to perceive the material world. You have little sense of self, and no idea of who you are, why you are dead, in what place you find yourself. But many memories lurk beneath the surface of your mind, waiting only for the most tiny of prods before vehemently bursting forth. These memories tell the tragic tale of your terrible fate, of the pain you suffered and inflicted; yet they may also contain the key to appeasement and redemption.
The stories of all the shades' lives are inextricably entwined. You were the authors of each other's destinies; your choices, conflicts and actions led to the unhappy, and perhaps untimely, end of all. You have inflicted so much pain upon each other that the wounds have never healed. They keep you tied to this existence. Can you resolve your differences, forgive each other, redeem your mistakes? Or is the impasse of hate and accusation to remain forever?
When playing Shades, you and one or two others will try to construct a haunting tale of tragedy and forgiveness from scratch. You will take turns narrating a piece of the story from the point of view of your character, and you will try to make these pieces into a coherent whole. But the rules of the game don't make it all that easy for you to succeed: Shades is meant as a challenging cooperative game. The challenge is for you and the other player or players to together tell a coherent, emotional tale; and to do it just by telling the tale, without any prior agreement and without talking about the story during the game. Sounds hard? It's easier than you may think, once you've learned to trust the other players and be sensitive to their wishes and ideas.
And the rules of Shades are specifically designed to help you build up that trust and that sensitivity. They will help you get to know what kind of stories the other players like, and how they try to signal their ideas to you. They will help you to learn to relinquish control over the story to others when that is called for, without taking a posture of deference. Not only will you be telling great stories and having fun doing it, you may also become better friends.