Space Opera

An opera company composed of aliens from a world no human is familiar with makes a concert hall appearance on Earth. Their music is strange, somewhat disconcerting, but the performance closes to rave reviews. The next day, every one of the aliens has vanished. They didn't leave by spaceship, and it seems impossible to believe they have successfully hidden themselves on a strange planet; so where did they go, and how?
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Roger Wool, a young dilettante who was enthralled by the "space opera," wants desperately to find the unknown world of origin of the musicians and hear more of their music. He persuades his wealthy aunt to sponsor a Terran opera company on a tour of the Galaxy, hoping to encounter the mysterious aliens, or their home world.
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But alien musical systems are NOT always well-received by people unused to hearing them. . .