The Doctor and Andric head to Earth to fix the TARDIS's chameleon circuit. Once there they face danger involving a newly regenerated Master and a feisty young air named Tegan.
When a teleportation accident goes badly wrong, Nyssa finds herself stranded on the freezing slopes of the Swiss Alps in 1963. But is it mere coincidence that she finds shelter in a snowbound school haunted by a malevolent poltergeist?
