Mermaids gather in shoals just beyond the breakers and sing, their voices deep as caves. The touch of their mucilagenous hands can heal leprosy: It restores sensation, rebuilds sloughed-off skin, uncurls clawed fingers -- it does everything but regenerate lost limbs.

      Lepers come to Calcutta from around the world to feel the mermaids' touch. They congregate on the beach to wait for tides that will carry them out to deep water. Many drown at the moment of their healing, dragged under by riptides when joy makes them weak and incautious.

      Their bodies, strangely mutilated of course, drift north and wash ashore, where they've been cataloged as victims of a serial murderer who haunts the dreams of everyone west of the Cascades. The mystery remains unsolved, but clues accumulate. The authorities are closing in.