Tag you are it!

Every chapter can be read as an one shot unless stated differently at the start of a chapter. There is progression of feelings over the chapters.

Ghost lost his childhood, he never got to be a kid and Soap does everything to give it back to him.

Ghost never had the opportunity to play tag with his parents, the only tag he ever played was with the enemy that either wanted to kill him or the other way around.

Ghost never got to build a pillow fort and lay on a soft blanket.

Ghost never got to be childish or careless.

Soap decided to change that.

or

Ghost finally experiences tenderness and fun.