 Using a Moog synthesizer and their natural gift of perfect pitch, one of the crew learns first to understand and then "speak" the Cygnan musical language, and is educated by Cygnan didactic films.They discover the Cygnans have travelled for 6000 light years - and six million earth years - escaping a home planet orbiting the progenitor star of Cygnus X-1, having discovered it was on course to collapse (forming the black hole that now occupies that point in space), searching for a new home; and, to do so, have raided numerous star systems for Jupiter-mass "gas giant" planets to use as fuel.The stop-off at Sol proves to be a particularly significant one as, having found every system they visited with habitable planets (whilst heading progressively further from the galactic center of the Milky Way) to already be populated with intelligent beings, their next destination is Andromeda, with the hope that a new galaxy may offer better results.