In 2368, the combined Borg–Cyberman fleet assaulted Cogen V and began assimilating the world and its people. In the process, they abducted the entire Cogenian population. However, the Cybermen then turned on the Borg, battling in the streets. The Cybermen took the Cogenians for cyber-conversion.
The USS Enterprise-D followed the fleet to Cogen V, but discovered that it had abruptly changed course and left. Commander William Riker, Lieutenant Commander Data and Lieutenant Worf, together with the Doctor, Amy Pond and Rory Williams beamed down into a Cogenian settlement, discovering it left in flaming ruins. Surviving Cogenian sentry drones attacked the group on arrival, but were soon shot down. They discovered Borg and Cyberman bodies left on the surface and soon learned of the battle amongst their enemies. (TNG - Assimilation² comic: "Issue 4")