Sofia and Amber visit an enchanted new world called The Mystic Isles where they encounter some magical new friends, including an enthusiastic unicorn named Skye and mystical human/hawk creatures called Windwalkers. Together with their new friends, Sofia and Amber must stop an evil Crystalmaster from covering the isles in crystals.
- Ariel Winter as Princess Sofia
- Darcy Rose Byrnes as Princess Amber
- Andrew Rannells as Skye
- Ming-Na Wen as Vega
- Jurnee Smollett-Bell as Chrysta
- Megan Hilty as Prisma
- Colin Salmon as TBA
- This will be the fifth TV Special movie in the Sofia the First series, following Once Upon a Princess, The Floating Palace, The Curse of Princess Ivy and Elena and the Secret of Avalor.
- Unlike the previous specials, this one will premiere in the Summer and on a Saturday.
- This is the sixth installment of the Secret Library story arc, preceded by "The Secret Library", "Olaf and the Tale of Miss Nettle", "The Tale of the Noble Knight", Elena and the Secret of Avalor and "The Secret Library: Tale of the Eternal Torch".
- This is the third time Sofia has someone coming with her on her Storykeeper adventure, first was Aunt Tilly in "The Secret Library" and the second was James in "The Secret Library: Tale of the Eternal Torch".
- The Mystic Isles was mentioned in "Day of the Sorcerers", foreshadowing this special.
- This special is the second time Andrew Rannells and Megan Hilty voice characters on the show. The first time was in "Beauty is the Beast" where Rannells voiced Morris the Goblin and Hilty voiced Princess Charlotte.
- This is the fifth time Sofia has a ponytail.
- ↑ "Craig Gerber Post 1". Twitter (January 20, 2017).
- ↑ 2.0 2.1 "Sofia the First: The Mystic Isles". Zap2it (May 18, 2017).
- ↑ 3.0 3.1 3.2 "DisneyTVAnimation Post". Tumblr (June 1, 2017).
- ↑ "Sofia The First - The Mystic Isles EXCLUSIVE CLIP". YouTube (June 22, 2017).
- ↑ "Sofia the First: The Mystic Isles trailer". YouTube (May 2, 2017).