Through the Ice by Piers Anthony, Launius Anthony, Robert Kornwise

participate in a quest," the Emperor continued. "If you do not participate, all of our worlds will suffer dire consequences. If you do, you have no guarantee of survival. Regardless of your choice, you will not be able to return home."
    The four Chosen sat in stunned silence. The Emperor was pulling no punches! He seemed to know all about all four of them—and knew that they were from different worlds. That they were some sort of key to some world-shaking project. Seth could tell by the reactions of the others that they were as amazed as he was.
    "Before I tell you exactly what your mission is, let me give you a little background information. First, we are all from the same Earth; a different awareness, but the same planet. There are, as far as we know, four separate planes or levels of awareness of Earth. Each is governed not completely but partially by a particular force. Earth Plane 1, where Vidav comes from, is driven by physical strength. Tirsa, who arrived at the castle first and already has some idea of what is going on, comes from Earth Plane 2, governed by mental ability. Seth comes from Earth Plane 3, where the driving force is science. Rame is from this plane, Earth Plane 4, where the governing force is magic. You are obviously not here accidentally. Your presence is needed for the welfare of all of the planes."
    At this point the large man named Vidav stood and said, "Erxvq naqstx zet tzas argqynofskx!"
    "One moment," the Emperor said. He gestured to Turcot, who handed each of them a small pill. "Swallow this. It will allow you to talk in the language of the person or group to whom you are speaking, as I am doing now. Rame does not need one, for all intelligent life on Earth Plane 4 can communicate with all other intelligent life."
    Seth found that hard to believe. The Emperor had been speaking in English! How could a pill affect anything other than the body? Language was something of quite another nature.
    But he saw Vidav and Tirsa taking their pills. The woman was so well proportioned that she made even the strange clothing look good. Her hair, which had seemed odd at first glance, now seemed appropriate to her; apparently it grew naturally in black and white tresses. Her eyebrows echoed it, being similarly zebra striped. If what the Emperor said was true, she was from another world, or at least another aspect of the one he knew, and spoke a completely foreign language. He wanted to understand her when she talked! So he took his pill, deciding to trust in what the Emperor said, even if it was nonsense.
    Vidav repeated his sentence. "What do you mean, we can't go home?" Apparently he had been too shocked by the news to ask the question immediately. That much Seth could understand; he should have asked about it himself!
    "There is a delicate balance, an equilibrium, in and between every plane," the Emperor said. "All creatures born in a particular plane stay in that plane; the balance of their world requires this. There is, however, a time immediately before death when a person is in a state of limbo, and not in one definite plane. Magic is a very powerful force, that extends into the state of limbo. By using magic we were able to draw you out of limbo just before your deaths. You were not dead; that would have been too late. Not only would it have stopped us from bringing you here, it would have made it pointless had it been possible. You were, in a sense, split. While in that brief period of limbo you were recreated by magic."
    He paused to gaze at them a moment. "I see you are having difficulty with this concept. That is hardly surprising! Let me put it another way: you are doubles of yourselves. Both you and your doubles look exactly alike, and your doubles are all alive in their respective planes, except in the case of Rame, who needed no such translation. By keeping one set of you on your own planes we have not disturbed Earth's balance. You have actually been borne to this world without harming our