Once Upon a Time, a Wicked Stepmother persuades her husband, the king, to lock the Princess in a lonely castle in the woods. One day, a Prince discovers the tower while hunting, and he spots the Princess. It's Love at First Sight, but communication is limited to facial expressions and gestures. A witch has pity for the pair, and sneaks a magical book into the tower. Whenever the Princess turns the pages in one direction, her Prince transforms into a canary. When she turns the pages the other way, he changes back into himself. In his bird form, he can fly up the tower and they develop a relationship.
The Queen visits her stepdaughter one day and spots the Prince at the base of the tower. Suspicious, she has various sharp pins placed along the windowsill. Her hope is that the Princess will stab herself if she leans in to flirt with the Prince. Instead, the pins strike him while in his bird form, and he falls from the tower. The Princess turns him back into a human, but the injuries last, and he comes to close to bleeding out before his companions discover him.
The Princess uses her bedsheets to escape the tower, then embarks on a quest to find and save her lover. She finds a coven of witches discussing various goings-on, and learns how to heal the Prince. She heads to her Prince's kingdom and saves him, but does not reveal her identity. In return, she requests that the king give her three items — the royal coat of arms, his standard, and the yellow vest he wore when he was found.
To avoid suspicion by the ladies-in-waiting and her stepmother, the Princess returns to her tower. When the Prince returns to the forest for another hunt, he avoids the tower. Still, she changes him into a canary and he flies to her room. He angrily berates her for his injuries, but she explains that the pins were her stepmother's doing, and then shows him the three items to prove that she is the mystery doctor who saved his life. He declares his love for her, and formally declares that he intends to marry her. Among the guests invited to the wedding is the Princess' father, who finally learns about what his wife put his daughter through. He has the Queen arrested, and everyone lives Happily Ever After.
"The Canary Prince" includes examples of:
- Bedsheet Ladder: How the Princess escapes the tower.
- Calling the Old Man Out: At the wedding, the Princess calls out her father for allowing her stepmother to be so cruel to her.
- Damsel out of Distress: By the story's end, the Princess can come and go from her tower more-or-less voluntarily.
- Distressed Dude: The Princess saves her Prince's life.
- Gilded Cage: The prison tower is functionally one of these, which fits in with the bird motif. Many ladies-in-waiting live in the tower with the Princess, she has a nice room, and she isn't being starved, but the ladies-in-waiting largely keep to themselves and she's completely cut off from the world aside from the occasional condescending visit from her stepmother.
- Girl in the Tower: The princess.
- Guile Heroine: The Princess is very clever, managing to sneak up on witches, and finding a way to permanently free herself from her prison while also saving her relationship with the Prince.
- No Name Given: None of the characters are named.
- Parental Neglect: The heroine's father wants to be a good parent, but he's very gullible and just takes his wife's lies word for it his daughter is happy in the tower.
- Shapeshifting Lover: The titular canary prince.
- Third-Act Misunderstanding: The Prince wrongly assumes it was the Princess who tried to kill him in his bird form with the pins on the windowsill. But she proves her innocence and that she actually saved his life.
- Wicked Stepmother: The cause of the Princess' trouble.
- Witch Classic: A few throughout the story. There's the sympathetic sorceress who gives the lovers the magic book, and a morally-neutral gathering of witches that the Princess spies on to learn how to save the Prince.