After an explosion, the Doctor realises that Middleton is located in an ancient volcanic caldera - with a new eruption about to start. The Doctor meets the army on the way to pick up their new guns, where they are attacked by magma creatures and the new guns explode when fired, killing most of the soldiers.
Upon detonation, the Doctor recognizes that Middleton is situated in a long-abandoned volcanic crater - poised for another eruption. The Doctor encounters the military on their way to obtain their novel armaments, where they are assaulted by molten creatures and the new guns explode when fired, killing most of the troops.