Meet Pipsqueak.
Pipsqueak, or "Pip" as he prefers to be called, has quite the imagination. There are times when he is a fearsome pirate, scourge of the seas of Equestria. There have also been times when Pipsqueak has fantasized about being a gallant prince, traveling the land, saving fair maidens, slaying wicked beasts, and being hailed as a hero by his peers. Not once did he ever imagine he'd get exactly what he wished for in the form of Princess Luna adopting him, making him an actual prince! Soon enough, Pip learns that being a prince isn't as glamorous as he thought it to be, and that there are more than a few downsides to being a part of the royal family. One in particular downside coming in the form of a nuisance named Blueblood.
On the other side of the coin, Princess Luna must adjust to her newly-found position of motherhood, balancing the task of providing her adopted foal as normal a life as possible for a young prince, while also making sure the nobility and paparazzi keep their hooves out of their business. Fortunately, this mare not only has the entirety of the Royal Guard, including her own Night Guard at her disposal, but her sister and niece also happen to be fiercely protective of the newest member of their family.