In a world of magical talking ponies, eventually everypony around will break into song and dance. And for those that don't join the festivities, somepony is bound to notice.
And for an unlucky Royal Guardspony, the one to notice his lack of gaiety just happens to be somepony you wouldn't want to disappoint. Will he be able to avoid being pulled into the raucous ruckus by this persistent pony? Or will his world be rocked by the rhythm of music found in everypony?