The Picture Book's Secret! What is a Princess? (絵本のヒミツ！プリンセスってなぁに？ Ehon no Himitsu! Purinsesu tte Nāni??) is the eighteenth episode of Go! Princess Pretty Cure.
- Air Date:May 31,2015
- Previous:Episode 17
- Next:Episode 19
- Opening:Miracle Go! Princess Pretty Cure
- Ending:Dreaming☆Princess Pretty Cure
- Cure Flora received Miracle Lily Dress Up Key and perform Lily Tourbillon for the first time.
- Haruka meets the author of her favorite picture book.
- The Cures' new Mode Elegant debuts and they use Trinity Explosion for the first time.
- Haruka meets Yume Mochizuki, the author of her favorite picture book.
- It is revealed that Yume is the headmistress of Noble Academy.
Haruka is making hairstyle for Puff and Yui tells her about the flower Princess story is witten by the author named Yume Mochizuki, is holding an autograph session and they go to her library.
At the Dys Dark, Dyspear is angry at the commanders for letting the Cures obtained the new Dress Up Keys and she want Twilight to know the situation and she tells her mother how to deal with them and give her the new Dress Up Key so she can defeat them.
Haruka explain the story about the Flower Princess, she was attracted by some animal and she likes flowers. She found a bird and was tricked by the witch and lock the princess. She is not afraid and escape from the witch and the bird blame himself for tricking her but she forgive him and the witch whereabout is unknown, leaving the plot unknown.
Haruka meet Yume and reveal that the story plot is not continue, which upset Haruka. Her daughter and her plan a story and discovered the picture of Flower Princess and the animals from the fans and they make this story. Haruka and Yui meet her again outside, saying that many fans had different idea about the princess' idea and leave things for render imagination.
Just then, Twilight appear and trapped everyone into the mirror using a staff to attract their despair's power. The trio transform and overpower by her strength. She took Haruka's book and attempt to burn it but Flora manage to take it back and she trust Yume's word about how to become like Flower Princess as her dream, this caused the book glow and received a Miracle Lily Dress Up Key and used it to overpower Twilight before using Miracle Dress Up Keys to switch into new Mode Elegant to perform new attack:Trinity Explosion. They manage to wound Twilight, making her hair untied and she tells them that she is the true princess before leaves with anger.
Yume saw Flora, who remind her of Flower Princess from the story. She and Shirogane have a chat in her office about how she open the Academy since 50 years and she is revealed to be the headmistress of Noble Academy.
- Haruka Haruno/Cure Flora
- Minami Kaido/Cure Mermaid
- Kirara Amanogawa/Cure Twinkle
- Yui Nanase
- Prince Kanata
- Yume Mochizuki
- This is the first episode where the Zetsuborg did not appear.
- Error: During the battle, the wrong footage is used. When Cure Mermaid inserts her key into the Crystal Princess Rod, the Ice Dress Up Key is shown instead of the Bubble key.