After Tirek's defeat at the hooves of Twilight Sparkle, the Alicorn Princess returns everypony's magic to its rightful owner. As a last cruel trick, the magic corrupted by the Centaur renders almost every stallion in Equestria infertile, dooming ponykind to extinction.

However, Twilight is able to come up with a solution: use pseudo-medical technobabble to explain that a fraction of the stallion population is still very much virile and able to breed. Thus, she creates the Trojan Brigade, an elite unit of stallions whose sole job is to ensure the continuation of ponykind.

Recommended to the Brigade by Rarity after a fling in Canterlot, Light Gust finds himself overwhelmed by the magnitude of the task, as well as his own uncertainties, convinced that sheer luck got him into the unit in the first place. Not one to lose heart so easily, he's ready to do whatever it takes to serve Equestria.

Whatever it takes.