Dissenters were a group of passive resistance fighters on the planet Rampart in the 24th century. They were considered heinous representatives of an ‘allpox,’ a threat to the lives of Rampartians by the government and were hunted down by Cephalic Security.
The government monitored the thoughts of its citizens using telepathic one-eye robots, routing out anyone with imaginative thoughts or who read fiction. Small groups of Dissenters were scattered to keep from being detected. Dissidents either joined them or committed suicide.
One group of Dissenters lived in Alastor, a group of networked caverns not far from CephCom, the headquarters of the thought-police in the city of Verity. Rebels had lived in the caves for 200 years, ever since the Rampart colony ship had arrived on the planet.
In 2366, the Alastor Dissenters led by Powell conducted an assault on CephCom. During the raid, some were captured and killed. Deanna Troi had a waking dream in which Sekhmet led a band of Other-worlders to aid the rebels in their assault. Those she saw assisting them were Caliban, Chiruwi, Coyote, Sir Gawain, Odysseus, Proteus, Rhiannon, Stagolee, Tezcatlipoca, and Uyemon. Lemuel Gulliver appeared at the last moment as a 100-foot giant to rescue Jean-Luc Picard, William T. Riker, Data, and Troi. Matriarch created an earthquake and storms that wiped out Cephcom. When Troi woke from the waking dream, she saw that none of those events had happened, but the Enterprise crew were beamed back to their ship.
In reality the assault had failed. The Dissenters were marched by security officers to a place where they would be executed. They halted when flocks of dragon-like haguya led by Rhiannon’s pet Saushulima appeared in the sky. These were native life forms, none of which were believed to exist on the planet. That they were both real and imaginary, living science fiction, confused the mind-filtering helmets of the thought-police. The sight broke the mind-wiping of Alfred Bowles, who had been reprogrammed to act as the Director of Cephalic Security. He ordered his troops to stand down. Later, Bowles found a way to transport aboard the Enterprise before his own troops arrested him. The government retained power after the incident, but several hundred Cephalic Security officers had quit. They rescued confiscated books and joined the Dissenters. (TNG novel: Gulliver's Fugitives)