Transformers: War's End (Transformers: War's End #2)

Trapped at the bottom of the Sonic Canyons, a group of Autobot scientists come face-to-face with Cybertron's greatest threat, Exarchon, and his lost armory. Can the peaceful Autobots hold out until help arrives-and with the Crystal City under siege, can the Autobots spare any help to begin with?