The path of black rocks leads Rapunzel and her companions to the Great Tree, an ancient, magical place. They encounter the unpredictable Hector and discover the moonstone magic formula. Hector proves to be a dangerous adversary to the group, and Rapunzel realizes that her only chance to save her friends is the uncontrollable Moonstone magic formula.
The path of black rocks leads Rapunzel and her companions to the Big Tree, an ancient, magical place. On their way to it, they encounter the unpredictable Hector, the last member of the Brotherhood and discover the Moonstone's uncontrollable Decay Incantation inside the tree. After traversing the interior of the tree, all of them ended up in a fight with Hector near the exit, who got pushed off by Adira and fell far down to the tree's heart. In a last resort to stop them all, he removed the spear inhibiting the dark magic, awakening it. That magic possessed him and eventually overpowered Rapunzel's companions, but was foiled by her usage of the second Incantation. This however, withered Cassandra's right arm when she touched Rapunzel in an attempt to stop the incantation, although her cries of anguish managed to achieve that. As the tree starts collapsing as a result, Adira went down to the heart with the magical spear while the Coronans escape.
- Mandy Moore as Rapunzel
- Zachary Levi as Eugene Fitzherbert
- Eden Espinosa as Cassandra
- James Monroe Iglehart as Lance Strongbow
- Jeff Ross as Hook Foot
- Paul F. Tompkins as Shorty
- Kelly Hu as Adira
- Jonathan Banks as Quirin (flashback)
- Kim Coates as Hector (debut appearance)
- The Great Tree (first appearance)
Powerful Objects of Supreme Power
- Magic Blonde Hair
- Moonstone (flashback & picture on scroll)
- Sundrop Flower (picture on the scroll)
- Shadow Blade
- The German version of the title in English is The Power of the Moonstone.
- This will be the fourth special, the others being Tangled: Before Ever After, Queen for a Day, Secret of the Sun Drop, and Beyond the Corona Walls.
- The alternative lyrics version of the Healing Incantation was sung by Rapunzel, and the spell activated new magic of Rapunzel's hair.
- There is a flashback of Rapunzel when she still has short brown hair, and it happens prior to Before Ever After.
- Varian and Quirin are mentioned in this episode.
- Quirin also appeared in a flashback when he is still encased inside the amber.
- Cassandra wears a new armored outfit at the end of the episode.
- This is the third time the closing theme More of Me is not featured, the previous being Secret of the Sun Drop.
- A clip from Next Stop, Anywhere and View From Up Here and clips from previous episodes are played during the beginning of the episode: "Freebird", "Tangled: Before Ever After", "Destinies Collide", "Rapunzel's Return" and "Race to the Spire".
- The way Lance carries Eugene in this episode is going to be similar to the way Varian will fall into Lance's arms in Cassandra's Revenge.
- Cassandra's face in this episode is similar to Varian's face in Secret of the Sun Drop.
- During the chase scene as Eugene's half of the caravan runs off the cliff and on to Rapunzel's the chain Hector threw at it, Hector himself, and his rhino is missing.
- Rapunzel's Tangled Adventure: Rapunzel and the Great Tree (Part 1). Retrieved January 21, 2019.
- Rapunzel's Tangled Adventure: Rapunzel and the Great Tree (Part 2). Retrieved January 21, 2019.