In the year 2130 a mysterious spaceship, Rama, arrived in the solar system. It was huge, but empty - apparently abandoned. By the time Rama departed for its next unknown destination many wonders had been uncovered, but few mysteries solved. Only one thing was clear: everything the enigmatic builders of Rama did, they did in threes. Eighty years later the second alien craft arrived in the solar system. This time, Earth had been waiting. Now Rama II is on its way out of the solar system.