The Dominators was the first story in season six of Doctor Who. Although the Dominators were the titular villains, it was the Quarks who later made appearances in Doctor Who in TV Comic.
A Dominator spacecraft lands on an island on the planet Dulkis, having just separated from its fleet. It absorbs the radiation of the island into its power reserves. The two Dominators, Navigator Rago and Probationer Toba, step out of the craft with their robot servants, the Quarks, in search of more fuel for their ship and fleet. Rago is intent on establishing an energy source by drilling through the planetary crust, which is at its thinnest in this part of the planet. Toba is more concerned about the possible aggression of the natives, appearing willing to eliminate them should they resist. Rago wants to use the natives for slave labor instead. Meanwhile, a Dulcian seacraft arrives at the island for an unauthorized trip. It is piloted by Cully, the son of Director Senex, a high-ranked member of the Dulcian council. The passengers include three Dulcians who think Cully has conned them when they find out there is no radiation on the island. They step out and are soon killed by the Quarks as ordered by Toba. Cully is not seen by them and thus he survives.
The TARDIS crew land and the Doctor assumes they’re in for a nice holiday, having visited “peaceful” Dulkis before. While the Doctor relaxes in a deckchair, Jamie blows up a beach ball given to him by the Doctor. Meanwhile, the Quarks destroy Cully’s craft. The Doctor, Jamie and Zoefind a war museum with old laser guns. They meet Educator Balan and his two students, Kando and Teel, who take the TARDIS crew to a survey unit for decontamination, finding to their surprise that the strangers are not radioactive at all. Kando tells them that the only nuclear blast on the island was an experiment conducted 172 years ago, after which all weapons were banned on Dulkis and the island was kept as an observation area for researchers and students. Meanwhile, the Dominators have begun to drill through the planet’s surface. Cully, having observed the Dominators near the TARDIS, finds his way to the shelter and warns people there of these warlike newcomers. The Doctor and Jamie leave immediately to check the situation, but soon find themselves at the Dominators’ spacecraft, threatened by Toba and the Quarks.
The Doctor and Jamie are taken prisoner on the Dominators’ ship, where they are forced to take part in tests. They are taken as representatives of the Dulcians by Rago and found unsuitable for slave labour — their bone structure is apparently too brittle and they fail (intentionally) at every test of intelligence. Cully and Zoe set off for the capital of Dulkis in Balan’s travel capsule. There they attempt to make the council and Director Senex understand the threat posed by the Dominators. This falls on deaf ears, as Cully is a known con artist. The council is more intent on debating the matter endlessly rather than actually doing something which might be misjudged.
At the war museum, the Dominators test the Doctor and Jamie with their reactions to the weapons there. The Doctor says there are two types of Dulcians, “the clever ones” who built the now-outlawed weapons and the likes of him and Jamie. This satisfies Rago and they are set free, with a warning to stay away from the Dominators’ mining area and the Quarks. Cully and Zoe return back to the island in order to find proof of Cully’s story, while the Doctor and Jamie head to the capital in another travel capsule. Teel and Kando have now had verification of Cully’s story from the Doctor and Jamie, and leave with Balan to witness this themselves in a very non-Dulcian manner. They are captured by the Dominators, examined and found to be “clever ones”, possibly suitable for slave labor. The Dominators set out to search for more slaves. Zoe and Cully arrive at the survey unit, just in time for the Quarks to start their destruction of the place as ordered by Toba.
Rago countermands Toba’s order and blames his subordinate for wasting the Quarks’ power resources. Zoe and Cully get out and are immediately captured by a Quark. The Doctor and Jamie have arrived at the capital. Despite their pleas, the pacifist Dulcians still doubt the aggressiveness of the Dominators. Senex states that the strangers are quite welcome to drill the planet’s crust, even though there are no minerals or anything else of value inside the planet. Zoe, Cully, Teel, Kando and Balan are now being tested for their suitability to slave labor and ordered to clear rubble out of the area in front of the war museum, with Toba and the Quarks guarding them.
Jamie and the Doctor have seen the destroyed survey unit on a monitor screen at the capital and are now rushing back in a capsule to see if Zoe is all right. They realize that Quarks may be waiting for them, so the Doctor alters the capsule’s flight path and lands them elsewhere on the island. They start searching for Zoe and the Dulcians. While continuing the exhausting task at the war museum, Zoe manages to distract the Quarks and Cully sneaks inside the war museum for a weapon. He aims at the Quarks from a small window, but is unable to shoot as his fellow Dulcians get in the way and then Jamie interrupts him. Meanwhile the Doctor is captured by Toba, who now finds out about Cully’s disappearance. Cully is spotted inside the war museum and the place is surrounded. Jamie shoots down a Quark, which leads to the destruction of the remaining part of the museum as ordered by Toba.
Toba is now certain that the rebelling Dulcians are dead. Rago is dissatisfied with Toba’s actions and a power feud ensues. Rago wins, and orders Toba to oversee the drilling. Cully and Jamie escape the collapse of the building to an underground atomic shelter, which has its only air vent blocked. They remove the rubble above the hatch and avoid suffocation. Rago finds out about the Dulcian council from the Doctor, who shows him how to get to the capital inside the travel capsule. The Doctor and Zoe stay behind at the Dominators’ ship under Quark guard. The necessary diversion is provided when Jamie and Cully, having mapped out the drilling sites and the number of Quarks on the planet, destroy another Quark by dropping a huge rock on it. Toba and a Quark immediately leave to investigate.
The Doctor and Zoe, now alone on the ship, find out that it has no generator, only an atomic storage unit — which explains the disappearance of the radiation from the island. Toba has halted the drilling and insists that the Quarks seek out the ones that attacked them. Rago arrives at the capital, but his improper addressing of the Director is protested. Rago orders a Quark to kill Tensa, who has been protesting the loudest. Rago queries the council for the Dulcians’ suitability for slave labour. The slaves are to be taken to the Dominators’ home planet where they will replace Quarks, which are needed for the front line in the war effort. The Dulcians who will not become slaves will die on their own planet. Rago orders Senex to start selecting suitable slaves and leaves. Meanwhile, Toba is interrogating the Doctor, Zoe, and the Dulcians on who destroyed the Quark. Balan is killed when no answer is forthcoming and the Doctor is next to be threatened.
However, Rago arrives and orders Toba to focus on drilling the final hole which hasn’t even been started yet. Rockets are to be prepared for the outer bore holes. They also need a “seed device” which is now near critical mass. Teel, Kando, the Doctor, and Zoe are taken to a drill site. Jamie and Cully attack a Quark who is guarding the prisoners and take their friends to the atomic shelter. Toba is once again intent on finding the troublemakers, but Rago commands him to use the Quarks only for drilling as their power levels are too low. The Dulcians are now unfit for slavery according to Rago. They will all die with their planet.
The Doctor, now aware of the drill pattern, explains the Dominators’ plan to others. The entire planet is to be converted into radioactive mass for the Dominator fleet’s energy reserves. When they launch rockets through the four bore holes into the planet’s crust, which is at its thinnest on the island, the crust will fracture and create a volcanic explosion. Once the atomic seed device is detonated inside this volcano, the entire planet will turn into radioactive magma. Jamie figures out that the center bore hole is very near the atomic shelter they’re in — they only need to dig a tunnel and grab the seed device once it’s dropped in. The Doctor prepares bombs from the chemicals inside the medical kit in the shelter. Jamie and Cully go outside and try to distract the drilling by destroying Quarks with these bombs. Instead of being distracted, Toba focuses on the center hole since it’s near completion. Rago chases the troublemakers with Quarks and they paralyze Cully’s arm. He and Jamie get inside the atomic shelter, where their tunnel is near completion. The tunnel is completed just in time and the Dominators drop the seed device into the Doctor’s hands — they immediately retreat for take-off to join their own fleet in the orbit.
The seed device turns out to be completely sealed and impossible to defuse. The Doctor needs to get it off the planet quickly before it will do untold damage. He orders Jamie and Zoe to return to the TARDIS and the Dulcians to retreat into the capital by travel capsule as the rockets will cause a volcanic eruption anyway, but only on the island. The Doctor runs to the Dominators’ craft and places the seed device inside, then rushes to the TARDIS. The rockets launch inside the planet’s surface and cause an earthquake and eruptions. The seed device explodes after the Dominators’ ship is airborne, destroying it completely and killing both Dominators. Outside the TARDIS, the Doctor looks rather pleased with his achievements, but retreats into the ship quickly as Jamie reminds him that molten lava is coming straight towards them…