McIntyre, Vonda N: Superluminal

From the ocean's emerald depths, where whales and adapting humans live in harmony ... to the rigors of inter-dimensional travel, the universe is order and laws; the universe is hierarchies, evolution, and space...Now a young pilot with a new bionic heart, a man from a plague-ravaged world, and a beautiful diver from the sea are about to discover that their destinies--and their souls--are entwined. A voyage to a distant planet, a message in a crystal, an accident, and a love affair have suddenly cracked open the known order of the Universe. Two women and a man are caught up in a mystery, and now they are changing every world they travel in, and every life they touch!