The violent, volcanic world of Hephastos is home to a colony of composers, painters, authors and poets, all striving to create the greatest works of art the universe has ever seen. But in pursuit of their goal, artistic collaboration has been taken a stage too far...

When the Doctor and Romana arrive, they discover the colonists have neglected their well-being and their once beautiful habitat has now succumbed to decay. What's more, they are enslaved to the Babble network which occupies their every waking moment. Every thought, however trivial or insignificant, is shared with everyone else and privacy is now a crime. The colonists are being killed and the Doctor and Romana begin to suspect that a malevolent intelligence is at work...