It is time for Rapunzel to get her official royal portrait done! A famous artist, The Giovanni, is coming to paint her portrait and she needs to choose a pose and subject matter that defines her and shows how she is unique. Apparently, she is having some trouble choosing, and Eugene and Cassandra are not being much help while they bicker about Eugene's lack of purpose or role in the kingdom, now that he is no longer Flynn Rider. But when he complains to the thugs at The Snuggly Duckling and fails to get them on his side, he decides it is time to find a job. Applying to different ads, Eugene tries being a baker's assistant, a carriage driver, and a cobbler. None of them work out. Just when he is about to give up, he manages to head off and capture a fleeing thief before the royal guardsmen can catch him, thanks to some personal experience in thievery. His success in capturing the thief inspires Eugene to join the Royal Guard.
He begins his training with an unimpressed Captain, and to everyone's surprise, especially Cassandra's, he does really well, even with the Captain and the other guards trying to sabotage him at every opportunity. Meanwhile, Rapunzel is still having problems choosing what she wants in her royal portrait, but she gets some help from her mother, who admits that she herself went a little too far with her royal portrait. She tells her daughter to show who she is, not what she can do. It is time for the final exam obstacle course for the Royal Guard training, and Eugene is feeling down about his chances. However, with a little pep talk from Cassandra, he regains his confidence. Even though the Captain tries his hardest to make him fail, Eugene passes the course with flying colors and is granted a probationary spot as a Royal Guard.
Meanwhile, The Giovanni arrives just as Rapunzel has finally decided on a simple portrait. Eugene, on his first day of duty as a guard, comes to visit her during her sitting but leaves the dungeon unlocked. A prisoner escapes, and Eugene was promptly kicked off the Royal Guard. However, something is fishy about Giovanni. Suspicions of him being a fraud are later confirmed when Eugene realizes that one of the castle's portraits have been stolen from the gallery and replaced with a fake. Although the Captain does not believe him, Cassandra does. They go to the docks to head off the thief, while the Captain finds out that Eugene was right when the real The Giovanni arrives. With some help from Cassandra, Fidella, Shorty, and Maximus, Eugene captures the fake Giovanni and the Captain apologizes for doubting him. While Eugene is clearly not meant for the Royal Guard, he does get a shot at being an instructor to help the guardsmen "think like a thief". As for Rapunzel's portrait, she decided to paint her own which represents the bond between her and her mother.
- Mandy Moore as Rapunzel
- Zachary Levi as Eugene Fitzherbert, Feldspar
- Sean Hayes as Pete
- Julie Bowen as Queen Arianna
- Eden Espinosa as Cassandra
- M.C. Gainey as Captain of the Guard
- Jeffrey Tambor as Big Nose
- Paul F. Tompkins as Shorty
- Diedrich Bader as Stan
- Fabio Tassone as Giovanni
- Artt Butler as Dale
- The title probably references the popular 1980-1988 detective series Magnum, P.I. A "P.I." is a "private investigator" or detective, as opposed to a member of an official law enforcement group.
- The way Eugene uses the arrows to climb during the training like he did climbed to Rapunzel's Tower from the film.
- Kait Ritter, storyboard artist on the show, has a cameo as one of the portraits in the gallery hall.
- Zachary Levi, who plays Eugene, also lends his voice to Feldspar, the doofy cobbler.
- Eugene knowing Italian was altered to Spanish for the Italian dub.