The Doctor left Derpy ten years ago to try to get home. Frustrated by his lack of success, he stays in the TARDIS, hanging idly in space. But when a delerious filly appears, he has no choice but to go back- and Ponyville is not as he remembers.

Sparkler and Dinky have been surrounded by shields most of their lives. One is to contain the Daleks, keeping them inside Ponyville. The other is to slow the Daleks down. Twice a day, the Daleks break through the second shield, and Dinky and Sparkler must lure them elsewhere; for some reason, the Daleks will go after them above all other ponies. They dimly remember a time when Rainbow Dash wasn't so obsessed with catching Daleks, when their mother wasn't sick, and when Daleks didn't haunt their dreams.

Their mother, Ditzy Doo, once told them of their father, a stallion who left without warning, without goodbye. He is the reason Dinky is so good with tools and why Sparkler understands ponies without knowing why. As the situation in Ponyville and their personal lives gets more and more desperate, they make a choice to try to find him. The problems in Ponyville have no ordinary cure, so why settle for an ordinary doctor?