A Human is transported to Equestria after he is injected with a so-called "serum". Where will his journey take him?

I have a conversation with Pinkie Pie. Can anyone translate for me?

After an atomic bomb has landed on his hometown, everything changed. Even after all of the time and research put into fighting the U.S., they still managed to do lots of damage. I guess that doesn't matter anymore, this place is different.

Pinkie Pie breaks the 4th wall yet again. A pony, who no-one in Equestria has met before, gets angry. Until one day, this one pony reaches a breaking point which causes him to do some rash actions.