The third exercise in alien science and diplomacy for former planetary surveyor John Bandicut (Strange Attractors, 1995; Neptune Crossing, 1994), his embedded translator stones, his cranial lodger (the serially immortal quarx--this latest version is female), his alien allies Ik, Li-Jared, and Antares, and the intelligent robots Napoleon and Copernicus. Flung off across the galaxy in a force-field bubble by the mysterious powers of Shipworld, Bandicut and companions sink beneath the ocean of a world whose amphibious Neri are threatened by hostile land-dwellers; even worse, the Maw, a deadly, unknown force lurking in the deep, is causing earthquakes and ocean currents that will soon sweep away the fragile Neri undersea cities. The Neri are at first hostile and suspicious of their visitors, but are then won over when Bandicut cures some of them from radiation sickness contracted during the salvage of a huge sunken wreck. As the friends come to grips with the local situation, Bandicut discovers that the wreck is really a starship, that the landdwelling Astari arrived in it--and that the Maw caused the crash! With the help of the now cooperative Astari, they gingerly probe the Maw--actually an ancient stargate that, damaged in space, fell into the ocean with its mission unfulfilled. Since the Astari vessel cannot be moved, the dying stargate agrees to complete its mission by sending Bandicut and friends through in their force-bubble. Another splendid adventure, with intriguing puzzles, first-rate problem-solving, and an impressive array of alien characters, motives, and methods.