Still weak and confused after his fourth regeneration, the Doctor retreats to Castrovalva to recuperate. But Castrovalva is not the haven of peace and tranquillity the Doctor and his companions are seeking. Far from being able to rest quietly, the unsuspecting time-travellers are caught up once again in the evil machinations of the Master. Only an act of supreme self-sacrifice will enable them to escape the maniacal lunacy of the renegade Time Lord.

A group of palaeontologists have been savagely attacked while carrying out a study of fossilised dinosaur remains in an underground cave system on twenty-fifth century Earth. A party of troopers and Professor Kyle, the only survivor of the attack, are investigating the deaths of her colleagues when they discover the Doctor and his companions at the site of the massacre. The time-travellers are immediately suspected. In trying to establish their innocence and find out who - or what - was responsible for the killings, the Doctor is confronted by an old enemy.

Tegan, the young air hostess who quite unintentionally became a member of the TARDIS's crew, wants to return to her own time, but when the Doctor tries to take her back to Heathrow Airport in the 20th century the TARDIS lands instead on the outskirts of 17th-century London. The Doctor and his companions receive a decidedly unfriendly welcome - but it soon becomes clear that the sinister activities of other visitors from time and space have made the villagers extremely suspicious of outsiders.

Matthew Waterhouse reads this classic novelisation of a Fourth Doctor TV adventure.The Doctor, Romana and K9 are heading for Gallifrey when they temporarily lose control of the TARDIS. The significance of this event is only revealed when they land, not on Gallifrey but on Alzarius. The planet's legendary Mistfall is approaching, a time when giant scaly creatures emerge from the swamps and go on the rampage, leaving a trail of death and destruction in their wake.

An unabridged reading of the final adventure for the 4th Doctor, novelised by Christopher H. Bidmead from his original TV scripts. The meddling presence on Earth of the Doctor's arch enemy, the Master, ensures the disruption of normality. Even he is horrified by the threat of total chaos he unintentially precipitates - until he finds a way to turn the imminent destruction of the universe to his own advantage. But the cost for the Doctor himself is terrible.