Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Unmissable.

The Doctor is summoned to Gallifrey where we discover that his society is so run-down that it's hardly surprising he wanted out. However, there is an assassination and the Doctor is suspected.This is a fascinating story and one that shouldn't be missed. The Master, previously in his last incarnation and now barely hanging onto life, is more filled with hate and rage than ever, a grim determination to finish off his old enemy despite the agony he is in providing a powerful image.But what really makes this story are the wonderfully surreal scenes in the world of the Matrix, years before the Nightmare on Elm Street films were made and arguably the most powerful images in the whole of the Tom Baker era.