Princess Pepper is a Phantom Detective. PhD for short.
When Pepper's tutor unexpectedly passes away, Pepper's left the only PhD in the Silverbright Kingdom. A silly rule in the handbook says she's too young to be head PhD in her kingdom, so the PhD delegation threatens to remove Silverbright's seat on the committee.
Then a phantom thief shows up in a charming town and terrorizes the citizens. Pepper convinces the delegation to give her the opportunity to prove she's capable of being head PhD, despite the rule. They give her until the end of the month to solve the most important case of her life.
Since only PhDs can see and hear phantoms, the townspeople begin to panic, and soon there's havoc in the streets of the once quaint town. Pepper must work swiftly to solve her first phantom thief case before the townspeople storm the castle, her kingdom loses their seat on the delegation committee, and Pepper's dream of being the youngest head PhD in history is ripped away.