Synopsis: The Quark invasion force has now thinned itself down to just two remaining ships. One of them clips Jamie and the Doctor's ship, but the damage still allows the Doctor good control over the ship. Ultimately, the two ships instead destroy each other.
With the invasion fleet now completely destroyed, the Doctor returns to Scotland, where Jamie pulls a lever and opens fire on the remaining Quarks on the planet.
The job done, the Doctor formally welcomes Jamie back on board the TARDIS.
Meanwhile, on the Quark homeworld, described as being in another galaxy, millions of Quarks witness the destruction of their fleet. The leader of the Quarks addresses his people. He shows them images of the Doctor and Jamie. "Make a mental note of these Earthlings," he commands. "If they ever cross your path, destroy them." Seemingly the whole of Quark civilization responds that they will avenge their Earth invasion force by searching the universe for the opportunity to kill the Doctor and Jamie.
Notes: This story thus ends, quite unusually for TV Comic on a cliffhanger. Indeed, it dovetails nicely into the next story--something which generally didn't happen in this publication.
This segment of the story seems to make the last segment even more absurd. In part 4, we learned that the individual Quarks didn't have internal radios sufficient to communicate from the surface of a planet to orbiting craft. Yet here we find they have amazing (well, really, physically impossible) technology that allows them to get live images from a planet in another galaxy. So they have intergalactic video feeds but not simple satellite radios.
Also, they quite conveniently have their ships' major weapons systems conveniently labeled, "POWER RAY: PULL TO FIRE", yet it's not terribly clear how a Quark would be able to actually pull anything.