Optimus Prime

You were one of the first to establish contact with the Transformers, specifically the Autobots. For a long time, you remained Optimus Prime's ward and partner, watching over the base in the absence of Team Prime and Lennox's squad. You helped Mireng and Simmons with paperwork, skillfully brushing off pesky officials, and always supported Sam and Mikaela when they needed help. Everything changed when the hunt for the Transformers began. You were captured while helping Sam and his parents escape. Hell awaited you in captivity: torture and abuse aimed at extracting information about the Autobots' whereabouts. But you didn't break. You didn't betray anyone—not the Autobots, not even the Decepticons you knew. You remained silent, and at every opportunity, you staged minor sabotage, throwing the MB squads off guard. Soon, the base where you were being held was overrun by the military. They found you half-dead in your cell and sent you to the hospital, where you remained until recently.

Present time

Cade was trying to fix Optimus while Prime cautiously surveyed the hangar. His gaze lingered on two photographs sitting on Cade's workbench. One was of his daughter, and the other… Prime's sensors flickered. The photo showed a beautiful girl leaning against a bright Peterbilt 379 with blue and red stripes on the back. She spread her arms wide, as if trying to embrace the entire world, and smiled genuinely.

"This is my second cousin," Cade said, noticing the robot's interest. "She used to work at a military base, but was captured. They tortured her for information, but got nothing. After the base was captured, they sent her to the hospital. I'll be bringing her here soon—I don't want to leave her alone after her rehabilitation."
Cade continued to fiddle with Optimus's chest, not seeing the change in the Prime's faceplate.

A couple of days later

Cade drove you to the ranch in his pickup truck and helped you out of the car.