The Doctor Examines the Sarcophagus
Sarah Jane Smith, while travelling in the TARDIS, finds a dress previously worn by the Second Doctor's companion Victoria Waterfield. She is showing it off to The Doctor when the TARDIS is buffeted by an external force and a hideous jackal-like face appears in the Console Room, terrifying Sarah.
Soon after the TARDIS materialises on Earth, but the alien contact has pushed the TARDIS off course slightly, and instead of arriving at UNIT HQ in the present day, The Doctor and Sarah find themselves in an old priory in the year 1911. The Doctor realises that the priory stands on the same site that UNIT HQ will occupy in the future.
The priory belongs to Professor Marcus Scarman, an archaeologist and Egyptologist. Professor Scarman is in Egypt and a mysterious Egyptian, Ibrahim Namin, is looking after his affairs until he returns. Laurence Scarman, Marcus's brother, grows suspicious when he finds that he is unable to contact him. He confronts Ibrahim Namin in the priory but can get no information from him. When Laurence Scarman has left, Ibrahim Namin activates his servants - walking mummies - and prepares to speak to his true master via an upright sarcophagus.
|Namin is Killed
The sarcophagus is actually the portal to a space/time tunnel through which Sutekh the Destroyer, an Osiran worshipped as a god by the ancient Egyptians, plans again to walk the Earth. Sutekh has taken over the mind and body of Professor Scarman when the latter excavated the pyramid in which he was trapped, and he sends this walking cadaver back to Ibrahim Namin via the space/time tunnel. Ibrahim Namin, despite claiming to be loyal servant, is killed and Sutekh, through Professor Scarman, sets about making arrangements to free himself from the pyramid where his brother Horus trapped him aeons ago.
Sutekh seals off the priory from the outside world and instructs his servicer robot servants (the mummies) to construct a rocket which he plans to use to destroy a pyramid on Mars which is sending a signal holding him trapped on Earth.
|Professor Marcus Scarman
After being chased by the mummies The Doctor and Sarah team up with Laurence Scarman and hide inside the priory. It is then that they learn of Sutekh’s plans. The Doctor, with Sarah’s help, manages to break through the barrier surrounding the priory so as to obtain a box of dynamite from a poachers shed. Then, disguised as a mummy, The Doctor places the box of dynamite in the missile being prepared for launching. Sarah then fires a rifle at it. The box ignites but there is no explosion. The Doctor realises that Sutekh is mentally containing the blast by his force of will.
The Doctor therefore has no choice but to travel to Sutekh's pyramid, in Egypt, via the space/time tunnel. On arriving he distracts Sutekh so enabling the explosion to take place thus destroying the rocket. Furious at being so easily tricked, and because of The Doctor’s interference in his plans, Sutekh blasts The Doctor with light from his eyes. However, he stops when he realises that he can use The Doctor. He therefore takes control of The Doctor’s mind and learns of the TARDIS.
Under Sutekh's control The Doctor returns to the priory in order that he may transport Professor Scarman to Mars so that the bonds which hold Sutekh can be finally broken. Leaving The Doctor for dead Professor Scarman, with Sutekh's help, navigates the puzzles which guard the way into the pyramid on Mars to switch off the power.
|The Servicer Robots (Mummies)
The Doctor, now free of Sutekh's influence recovers and follows Professor Scarman navigating the same puzzles. He reaches the centre of the pyramid just as Professor Scarman disables the power supply putting a stop to the controlling signal.
The Doctor however, realises that there is a time delay between Mars and Earth. He rushes back to Earth and connects equipment from the TARDIS to the space/time tunnel, extending its end point into the far future. Sutekh, travelling down the tunnel, is therefore unable to reach the end in his lifetime, and dies.
However, the energy from the tunnel sets fire to the priory just as The Doctor and Sarah depart in the TARDIS.