The second Princess Principal film concluded with the major revelation that Prince Richard and his forces from the re-conquered New World were the mysterious third power that entered the spy game between the Kingdom and Commonwealth. This revelation has left Charlotte in a delicate situation. As she is lower than Richard in the line of succession—and thus doesn't need to be killed for him to assume the throne—he offers her a place by his side as they share similar goals.

This is the driving dilemma of the film. Like Charlotte, Richard desires a world where the Kingdom and Commonwealth are not separated. He wants to go a step further by allowing all countries in the world to be equal and independent. If the two of them join forces, they would be unstoppable after the Queen's looming death, since there would be no one of royal authority to stop them—except for Mary.

Herein lies the big difference between Charlotte and Richard. Richard believes the ends justify the means. He is willing to commit not only fratricide but regicide as well to get his way. Even the killing of a child is a price he would gladly pay for his cause. Charlotte, on the other hand, is far less pragmatic. She has a line she won't cross, and believes she can gain the throne and bring about a massive reformation without war or a bloody coup. Yet, the temptation is there. With Richard, she can get what she's been working towards—all she has to do is stand aside and let it happen.

To make this dilemma hit home on a personal level, this film largely focuses on Mary. Suddenly, with the crown prince dead and her grandmother bedridden, she becomes the heir apparent despite being a literal child. The Kingdom is split into factions: the traditionalists want Mary on the throne, while the young nobles want Richard. Yet, Mary is just a sheltered orphan girl, raised in near isolation with her governess acting as her mother, teacher, and only friend. With the string of assassination attempts, her life becomes lonelier and more restrictive as her great uncle, the Duke of Normandy, prepares her to take the throne. The struggles Mary faces hit hard emotionally, and it's impossible not to root for her and fear for her as the film reaches its climax.

As for the visuals, this is the least impressive of the Crown Handler films to this point, though that's not to say it looks bad in any way. Almost the entire film takes place in the royal palace, with only a single action scene over its runtime, so there's not much to show off animation-wise. Meanwhile, the music is the same as in the last two films, which is nothing new or noteworthy.

All that being said, this is easily the best of the Crown Handler films so far. It's full of high-stakes tension as our heroes play their spy game while fighting an internal battle between pragmatism and idealism—with a young girl's life hanging in the balance. To top it off, the film ends with a climax that completely upsets the status quo and promises a completely new direction for things going forward. It's simply a great watch.