The experiences of an individual define what they will become, like definitions defining a certain object to explain the otherwise unexplainable. This is the concept of Aizawa's experiences that developed him into the beloved teacher of 1-A—and it all began as a teenager. Warnings Inside.

Some of Aizawa's students try and show their teacher their skill at the popular string game. They in turn, however, are shown the skills of a man who uses string, or it's pro-hero capture weapon equivalent, every day.

Hizashi's birthday is in a week and he's excited to celebrate it with his best friend and secret crush, but things don't go exactly as planned when Shouta is hit with an age regression quirk.

When Britain tries to punish America rudeness, he accidentally turns him back into a child. With no memory of Britain leaving him or the Revolutionary War, America and Britain rekindle their relationship as brothers. All seems well for the two, but the other countries start to worry about this unnatural relationship and whether it is right. Chibi!America/Child!America.