It has been a week since Rapunzel's hair grew back, and in that time she has been having nightmares that she believes are telling her something. Cassandra still refuses to allow Rapunzel to tell Eugene or anyone about the night they snuck out, and that it was her fault that her hair grew back in the first place. She is worried that if word got out she could be sent to a convent. As far as everyone knows Rapunzel simply woke up that morning with long hair. Rapunzel does not like keeping secrets from Eugene, but to Cassandra's plea, she says nothing. While Eugene and Maximus are out visiting the Thugs at The Snuggly Duckling, Cassandra comes to Rapunzel with the word about someone who could help them unravel the mystery of her hair. The person she is suggesting is someone named Varian, who is known to be some kind of wizard. Fairly little is known about him. Rumors say that he is dangerous, but either way, he is Rapunzel's best chance of finding out more about her hair.
Rapunzel, Cassandra, and Pascal ride Fidella to a village outside the kingdom, passing the Snuggly Duckling where Eugene and Maximus spot them. Seeing their chance to escape from Big Nose's long poem, they follow them to a rundown mill. Rapunzel, Cassandra, and Pascal go inside, and suddenly get their feet trapped in some kind of goo. They are confronted by the mysterious wizard known as Varian, only to find that he is in fact just a young scientist who studies alchemy. After freeing them from his specially made goo, Rapunzel and Cassandra get down to business on why they have come. Varian begins examining her hair, and the first thing they discover is that it no longer processes its magical healing powers. Varian then has Rapunzel restrained to some kind of machine, where they will run a series of tests on Rapunzel's hair. During the tests, Eugene, observing from a window, thinks that Rapunzel is in trouble. He charges in to rescue her, only to realize that she is in no danger at all. Varian recognizes Eugene as Flynn Rider, however, he is mistaken for the character in the books where Eugene took the name from. Suddenly, an earthquake trembles through the workshop. Varian remembers he needs to bring in a device that will print out the results of the tests.
Accompanied by Eugene, Varian finds what he is looking for and at the time shows Eugene his biggest project of all. Underneath the village, Varian has built five machines that will provide his village with hot running water. To Eugene, they look unstable, and the chemical reactions they are triggering are the source of all the trembling. Varian assures Eugene that nothing can go wrong, but Eugene thinks otherwise. Meanwhile, Rapunzel is down to only twelve tests, and tremors caused by the machines are becoming even tenser. Eugene gets worried, that he takes Varian aside and pleads for him to shut off those machines. So he goes underground to turn them down, only to realize it is already too late. The condition of his machines become critical, setting off a series of earthquakes just as the tests on Rapunzel's hair are complete. However, Rapunzel is trapped in the machine and Eugene is unable to free her. Pretty soon, the whole building begins to collapse. Rapunzel tells Eugene to save himself, but he chooses to stay with her as the ceiling collapses on top of them. However, they are saved by a protective shield formed by Rapunzel's hair.
Afterward, the chaos is over, but Varian's village is all in the rubble. Varian apologizes to his saddened father for the damage of the village. Most of all, the results of the tests on Rapunzel's hair were lost when the building collapsed on them. Both Rapunzel and Eugene agree to no longer keep secrets from one another, and Rapunzel finally confesses the truth about what actually happened on the night her hair came back. Hearing that Cassandra helped her sneak out, Eugene initially plots to turn her in but decides not to after realizing how important she is to Rapunzel. He nevertheless shows gratitude in Rapunzel's honesty.
Unbeknownst to the group, one of the black rocks that made Rapunzel's hair grow back begins to sprout outside the kingdom.
- Mandy Moore as Rapunzel
- Zachary Levi as Eugene Fitzherbert
- Eden Espinosa as Cassandra
- Clancy Brown as King Frederic
- Julie Bowen as Queen Arianna
- Jeffrey Tambor as Big Nose
- Jeremy Jordan as Varian
- Jonathan Banks as Quirin
- Donna Murphy as Mother Gothel
- Rapunzel's hair no longer possesses its healing powers but is revealed to have acquired a new power to create a protective shield.
- The Healing Incantation is briefly heard in this episode.
- The Pub Thugs reveal to Eugene that Hook Hand is on a world tour and that he has a brother named Hook Foot.
- The title of the episode is a pun to the phrase 'What the Heck?!'.
- The title is also said by Eugene after Rapunzel's hair creates a shield to protect the couple.
- This episode takes place one week after the events of Tangled: Before Ever After.
- This is the first appearance of both Hook Foot and Varian.