On one of the facets of the Great Crystal, the Gyroscope wheel turns—a stabilizer of the slowly growing space of the Institute courtyards, where there is no entrance for evil, violence, and other foulness. An attempt to influence the Gyroscope in order to rapidly expand the “space of goodness” fails… And all that remains for the novel’s heroes—“The Sound of Tapping Chess Horses”—is to make sure the wheel never stops.