The newly-regenerated fifth Doctor must rely on his friends to survive as the regeneration threatens to fail.
The Master reveals to the trapped Adric that he has a further trap set for the Doctor.
Nyssa and Tegan follow the trail of blood away from the Cabinet, trying to find the Doctor.
Realising the true nature of Castrovalva's reality, The Master, seeing all is lost, flees to his TARDIS.
The arrival of the TARDIS is observed by three Urbankans via their manopticon devices.
Aboard the Urbankan ship, a Grecian philosopher reveals a bizarre secret about Monarch and his methods.
Panicking, Tegan accidentally pilots the TARDIS into space, while Lin Fitu betrays the Doctor and Bigon.
Nyssa and Bigon keep the Urbankans distracted and Adric decides exactly whose side he is on.
On the planet Deva Loka it is almost paradise with a year-round temperate climate and non-hostile natives.
The Doctor and Todd are locked in a cell, while Adric manages to persuade Hindle he's on his side.
The Doctor observes that the Kinda have a sense of humor, but Hindle is unamused.
Tegan confesses the contents of her dream suspecting that a Mara has passed into the real world through her.
In a 17th Century English village a comet explodes in the night sky and the villagers are attacked.
Discovering an energy barrier in a cellar wall, the group are attacked by a figure dressed as the grim reaper.
Adric manages to escape while Tegan is brought under the complete control of the Terileptil.
The Terileptil heads to the city of London to enact his deadly plan, leaving Tegan to do his bidding.
The Cranleighs ask the Doctor to play cricket and then join them for a masked ball.
The Doctor stands accused, despite Lady Cranleigh knowing he is innocent.
Deadly androids are protecting a bomb buried beneath the Earth from all investigation.
With her crew vanishing mysteriously, Captain Briggs assumes the Doctor is the guilty party.
The Cybermen are released from their silos and are on the march, attacking Briggs's crew.
The Doctor realises the freighter is now a huge bomb and sends it back through time.
A Concorde passenger jet seemingly vanishes on its final approach to Heathrow Airport.
The Doctor must try to work out why the mysterious Kalid has drawn them into the Jurassic period on Earth.
Deep inside the citadel, the Doctor discovers the legendary Xeraphin who were believed to have been wiped out long ago.
The Doctor must try and return the Concorde passengers back to their own time.