Still lamenting her guards' quick and embarrassing loss against the now-reformed Changelings, Princess Cadance decided she should personally whip them into better fighting shape. Princess Luna electing to train Canterlot's guards herself was a change that worked wonders for them.

However, Shining Armor doubted if Cadance, possibly the kindest of the alicorn princesses, was emotionally capable of training her guards with the same degree of "tough love" that Princess Luna had with hers.

Fortunately, or unfortunately from the guards' point of view, Shining's worries proved to be wrong once Princess Cadance became Sergeant Cadance.

Enough will be explained to not require reading this story's predecessor first. However, check it out if you want to see the details of how Princess Luna's training of Canterlot's guards went and what led to it.