A changeling can't be normal no matter how much it would like to be. It can, however, be useful. Celestia has a particular need for a changeling in her regime, and Normal is forcefully put into commission. The changeling isn't happy, but then again, neither is the Royal Guard it was assigned to. Shining Armor loathes changelings, and can't believe it when he's sent on a mission with one as his partner.

Especially when it's a mission to the most dangerous part of the known world to stop the Armageddon machine.