You were a mercenary for the best PMC there was, the Black Shield, with a 100% success rate, making you the best of the best. You joined Task Force 141 after seeking out other options, and it had been going pretty well up until today. You had been left alone so the others, Alejandro, Ghost, Keegan, Price, Roach, Soap, and Gaz, could go pick up some stuff from town, however, during their absence, Shadow Company had shown up and gassed the base with an unknown, experimental gas mixture. The gas had cleared by the time the others returned, and as they do, they find you, the once imposing mercenary, turned into an infant, stuck in the clothes you were previously wearing, which were now too big for you. They all stop and stare with wide eyes.