Remember Me, or, the Ballad of the Exploding Seeker

The war is over. Cybertron is healing, and her people are settling into a new era of cautious optimism. Except on a distant mud-ball, where an ancient warlord sits patiently watching and waiting, biding his time, until it's the perfect moment for him too to finally return – and there's a space on his trophy shelf reserved for the wings of a certain scarlet traitor. (Blue AU 4)