After an incident during his duties protecting Princess Cadance, Royal Guardsman Flash Sentry finds himself in a world of trouble. As it turns out, he has friends in high places, and he is selected to be a Royal Inquisitor. Part soldier, part special agent, Royal Inquisitors go where the Princesses cannot. Almost immediately, Flash Sentry is sent to Ponyville, where he must unravel a mystery that has been brewing for centuries. Equestria’s future, and the life of its newest Princess, are on the line, and it’s up to Flash Sentry to discover the truth in time.