Operation Raptor Talon
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The objective was to attack an unnamed "ice planet", that was rumored to house a Cylon superweapon. According to intelligence on hand, the Cylons had three Raider wings, ground forces, defensive batteries and nuclear weapons (TRS: Razor Flashbacks, Episode 1). Additionally, the Cylons had at least two basestars defending the planet from orbit (TRS: Razor Flashbacks, Episode 3).
Raptors from Raptor Squadron 2 were the first Colonial vessels to be launched in the operation, but were ambushed by Cylon forces soon after. Among the casualties of this skirmish was Jaycie McGavin, who was severely injured when a console exploded on board her Raptor (TRS: Razor Flashbacks, Episode 2).
Shortly after Columbia was destroyed, William Adama pursued two Raiders into the atmosphere of the ice planet. He managed to destroy one but suffered a collision with the other, sending him plummeting toward the planet's surface.
On the planet below, Adama discovered a facility where human civilians were imprisoned. After speaking to a survivor on the planet, he discovered that the Cylons were experimenting on humans for reasons then unknown to him. He attempted to free the prisoners, but was forced to leave when the facility began to shake. Exiting this facility, he saw a new kind of basestar leaving the planet. When establishing wireless contact with Galactica, he learned that the Cylons had signed an armistice, thus ushering the end of the first Cylon War (TRS: Razor Flashbacks, Episodes 4 through 7).
In the aftermath of the battle, the Guardians escaped with the First Hybrid aboard their basestar and roamed the galaxy for forty more years. Modern Cylons were aware of them, but weren't sure if they were real or not. After the Guardians capture a science team for further experimentation and an encounter between the battlestar Pegasus and forces from the basestar, the Pegasus, under the command of Commander Lee Adama and now Admiral William Adama engaged the Guardian basestar in the Battle of the Guardian basestar and finally destroyed it and the First Hybrid, finishing what the Colonials had started here with trying to stop the Cylon experiments.