Time-Flight

On a standard flight from New York to London, Concorde Golf Victor Foxtrot is nearing Heathrow Airport when its signal begins to break up. Before long all trace of the aircraft is lost - the Concorde has disappeared! Arriving at Heathrow shortly after, the Doctor, along with Nyssa and Tegan, is enlisted by the authorities to help in the investigation of the missing craft.

Boarding a similar Concorde, and following the same flight path, the Doctor finds traces of disturbance and, although they arrive safely at Heathrow, they discover that they have travelled 140 million years into the past!

As the Doctor and the crew struggle to come to terms with their situation they are faced with many important questions - What is the significance of a mysterious nearby citadel and who is the strange magician Kalid who lives there? How can they evade the deadly Plasmaton energy creatures? And just how are the events on prehistoric Earth connected to the fate of an ancient race of aliens called the Xeraphin?

As the Doctor struggles for answers he discovers that many of them may be explained by the unexpected appearance of an old and very unwelcome enemy.