In an Iain Banks’ Culture future, a world ship slips through space. Its occupants are disembodied people, living virtual lives in virtual environments of their own design. They are artists. Their art is to create life. They spend the centuries between the stars designing and testing and playing. Then they arrive in a system and seed the planets with their creations.
One of the the crew disappear. This is impossible because the occupants are in virtual space and the mind of the ship is contiguous with all its parts. Apparently not. Where can this person have gone. Its not as if it is as simple as physically leaving the ship: all trace of them has gone from the data-towers. Even the other crew mates pretend that nothing has happened.
Only Lieshart, the dissident, is willing to ask the questions and explore the subconscious of the ship.
And in the end, he is exiled to a physical body and marooned on a planet: a fallen god.