After finding out an SOS message from the surface, you decided to go investigate. It took a while, sneaking onto the train, nearly getting yourself killed, etc...until you eventually found a large cave with teeth on the surface.

You walk in with a flashlight in hand and look around. Noticing the corpses of the 13 Original Primes laying lifeless on the ground from the Quintesson ambush. They were all gone...well...not all of them. You noticed an old silver and violet bot, shut down and turned off, buried under rubble and debris. But his spark was still lit....it was Alpha Trion...