After the Doctor is attacked by a group of mysterious gunmen, he discovers he is the physical double of the famous scientist Salamander.

Jamie and Victoria agree to accompany Astrid to Hungary to observe Salamander's activities.

Jamie and Victoria join Astrid into attempting to rescue Denes but Salamander becomes suspicious of them.

The Doctor persuades Bruce to help him infiltrate Salamander's research centre while Salamander takes drastic action to prevent Swann finding out the truth.

The Doctor discovers the true link between Salamander and Kent while Astrid tries to convince the shelter inhabitants they have been lied to.

England, the near future. UNIT is providing security and scientific support for the Stahlman project, an attempt to tap the Earth's core for energy. But things are already going wrong…

The Doctor has vanished from the Inferno project… or has he? He finds himself in the same place, but everyone has changed… and the drilling is closer to its deadly conclusion.

In a parallel England, the Doctor tries desperately to convince his captors of the immense peril they are in. But they are convinced he is a spy. And penetration zero is getting close…

The parallel Inferno has broken through the Earth's crust, unleashing terrible seismic forces and dooming the planet. The Doctor hopes to return and save his world. But the bestial primords are closing in...

The Doctor is trapped in a parallel world that is going up in flames. Can he escape in time to save Earth in his own universe?

The Doctor has escaped the catastrophic destruction of a parallel world. But can he stop Stahlman before he destroys this one?

When a Nestene Energy Unit is stolen and a radio telescope sabotaged, the Doctor is contacted by a Time Lord who tells him his old rival the Master is responsible.

Attempting to find out where Jo encountered the Master, the Doctor heads to the circus where he falls foul of Rossini.

The Doctor and the Brigadier head to Farrel's factory but the Master and the Autons have already left and are distributing plastic daffodils around the country.

The Doctor discovers the plastic daffodils are designed to fire a spray that asphyxiates people, causing havoc prior to the Nestene's arrival, but before he can alert anyone he and Jo are captured by the Master.

The Doctor attempts to test his new dematerialisation circuit by taking Jo to Metebelis Three but instead the TARDIS arrives in the hold of a 1920s cargo ship.

The Doctor and Jo attempt to find a way out of the Scope but, when Vorg attempts to entertain the Minorans, the crew of the Bernice suddenly become a lot more dangerous.

The Doctor and Jo return to the Bernice to try and aid their escape but find themselves pursued by the Drashigs.

The Doctor escapes from the Scope and joins forces with Vorg to try and save its inhabitants but Kalik is still determined to use the Drashigs to start a rebellion.

While the Doctor carries out an investigation into ESP, Mike Yates asks Sarah to look into some strange goings on at a meditation centre he's attending.

Lupton forms an alliance with the spider to steal the Doctor's blue crystal, while Sarah and Mike attempt to alert people to what they've seen.

The Doctor and Sarah head to the meditation centre to try and get the crystal back while Lupton prepares to return it to Metebelis Three. But all their plans are disrupted when it is stolen by Tommy.

Sarah is captured by the spiders' guards while the Doctor tries to help Arak and the others strike back against the spiders.

The Doctor escapes from the spiders' larder only to encounter the Great One, while Sarah makes a deal with the Queen Spider.

K'Anpo persuades the Doctor he must face his fear and return the crystal to the Great One.But first they need to get past Barnes and his men.

The Doctor and Sarah return to Earth in the present day to find a strangely deserted village and woods stalked by white-clad figures.

The Doctor suspects Crayford brought something to Earth in his rocket, as he and Sarah find themselves hunted by UNIT.

The Doctor is captured by Styggron and left to die in the destruction of the fake village but Sarah escapes from the disorientation chamber to try and rescue him.

The Doctor and Sarah reach Earth and try to warn the research centre about the Kraal invasion before Styggron unleashes his virus.