The mummies have nearly completed the Osiran missile destined for Mars to destroy the force field keeping Sutekh imprisoned. The Doctor and Sarah Jane find a way to deactivate part of the force field allowing them acquire a supply of gelignite from the poacher's storage room. Laurence tries to awaken his brother Marcus but Sutekh is in complete control. Posing as one of the mummies, the Doctor tries to place the explosive at the missile site but its ineffectual again thanks to Sutekh's mental powers. The Doctor decides it's time to visit Sutekh himself to distract him. There is a price to pay however.
—garykmcd