All conflicts have arms races. For the Earthlings, their superweapon would destroy Equestria's barrier. For the Equestrians, their superweapon could cripple the Earth's military advantage.

In a mission to deliver the Earth's trump card, the two finest weapons of the Earth and Equestria meet, intrinsically changing the fate of one side.

Twilight's battle against Starlight seems endless. No matter how hard she tries, she can't get the edge on her foe unless she ramps up her power output. But that could seriously hurt Starlight. And Twilight won't hurt Starlight, there must be good in her somewhere that can be redeemed! A look into a certain future changes that opinion.