The Doctor has been staying on the planet Hitchemus for the past few months where he has been learning to play the violin from gifted young composer Karl Hassan. Hitchemus is a planet with two distinctive features -- the humans who live there have a formidable reputation for composing, playing and appreciating a wide range of music -- while its tiger population is showing unusual signs of intelligence.Although Anji is greatly unnerved by the sight of a tiger taking a book out of a library, no one is prepared for the day when the tigers take over the planet. Their demands are unusual though -- they want to be taught to play instruments as well as the humans, and to this end kidnap all of the planet's most eminent musicians.Why are these tigers so intellectually advanced, and can the population of Hitchemus resolve their conflict to avoid civil war? The Doctor sympathises with the tigers and humans alike, but needs to help both parties to resolve their differences before they both begin to see him as a traitor...