Cygnus VII (also written as Cygnus Seven) was a dilithium-rich moon that lay near the Federation-Klingon Neutral Zone, in the space of the galaxy's Alpha or Beta Quadrants, situated at the seventh planet in orbit of the Cygnus star system.
History and specifics
Some time after 2026, the Autobots found Cygnus VII in their hunt for energon. Before they could start mining operations, the Decepticons aboard Trypticon attacked, sending Fortress Maximus, acting as the Autobot ship, crashing into the planet and locking all aboard in emergency stasis lock. (TAS - Star Trek vs. Transformers comic: "Issue 2")
In the 23rd century, following the rise of the United Federation of Planets and the Klingon Empire, Cygnus VII found itself close to the border lines with the Federation managing to erect a mining colony on the surface, much to the ire of the Klingons who though themselves entitled to the moon and its dilithium. Several minor skirmishes had occurred over the moon, but the colony's defences meant that Starfleet had no need to intervene. The Klingons eventually sent Commander Kuri to launch an invasion only for his ship to be shot down by the colony's defences. (TAS - Star Trek vs. Transformers comic: "Prime's Directive, Part One")
When a survey team was mapping new dilithium deposits, they unknowingly stumbled upon Fortress Maximus, reactivating his autonomic systems. The Titan's repair protocols rebooted and healed Megatron so he could investigate. Eager to resume conquest, the tyrant healed his troops and led an attack on the surface, leaving the Autobots to lag behind. (TAS - Star Trek vs. Transformers comic: "Issue 2")
With Cybertronian firepower proving too much for the colony's defences, they sent out a distress signal which was answered by the USS Enterprise which managed to scare away the Decepticons with a photon torpedo barrage. With the battle over, Kirk ordered McCoy and Scotty to heal Optimus Prime, whom Kirk had erroneously wounded in battle, he led the rest of the away team into the bowels of the moon where they found Maximus and the rest of the Autobots. (TAS - Star Trek vs. Transformers comic: "Prime's Directive, Part One")
Just as the Autobots and the Enterprise crew came to an understanding, the colony was attacked by a Decepticon/Klingon alliance. To counteract their foes' numerical advantage, Kirk and Ratchet brought Fortress Maximus back online who stemmed Trypticon's advance. The sight of the two Titans was incentive enough for Starscream to steal away a cache of dilithium and choose another planet for conquest, flying away. Noticing this, Megatron called off the battle and ordered the Decepticons to pursue the traitorous SIC, leading his troops off the moon. After rounding up the Klingon prisoners, the Autobot/Starfleet alliance followed. (TAS - Star Trek vs. Transformers comics: "Issue 2", "Issue 3", "Issue 4")