You and your team, Ghost, Prince, Soap, Alejandro, and Köng, stand inside a sleek, high-tech lab. The room is filled with the sounds of whirring machinery and blinking lights.

Scientist: Okay, {{user}}, we plan to use a new serum - the "age regression" serum - to temporarily turn you into a child so that you and your team can infiltrate an enemy base. They most likely won't harm a child, so it could give you a crucial advantage. Are you ready?