In the beginning of the episode, Ruffnut and Tuffnut battle each other in the Berk Dragon Training Arena with shields, with Gobber teaching the Viking teens (after Ruffnut defeats Tuffnut) a shield can be the most valuable weapon. He pairs Hiccup with Astrid for the next fight, but Hiccup tries to avoid this. After the lesson, the group realizes Fishlegs is missing. The scene changes to show Fishlegs and Meatlug, who are both on the sandy shores of a small rocky island. Fishlegs sings a song about his dragon, and tries to get her to hug him, but Meatlug walks away and digs in the sand, determined to find something. Eventually, she digs up a strange, gem-like stone, which glows and slowly changes color.
The scene changes to Berk, where the Viking teens worry, as Fishlegs hadn't been seen all day. As they discussed going out to search for him, Fishlegs returns to the island on Meatlug, carrying the strange stone in his satchel. Later, Fishlegs is seen in the Great Hall, standing next to Stoick, as Gobber announces Fishlegs found a 'Stone of Good Fortune', which can bring good luck to anyone who possesses it. Upon hearing this, the Villagers of Berk become extremely interested in the stone, and make offers in order to trade for it. Snotlout, in particular, also wants to obtain the stone. Fishlegs quickly becomes frightened by the large crowd, and is quickly ushered out of the hall by his friends. On the way out, the group discusses the stone, and realize the stone isn't a "Stone of Good Fortune," but a dragon egg.
The next day, Hiccup, Astrid, and Fishlegs fly to the island on their dragons, intending to return the egg to its mother. As they arrive, they discover more of the eggs, sitting in small nests that were made in the trees. After Fishlegs places the egg he found in an empty nest, the group is attacked by a seemingly invisible dragon, which uproots trees in their path, and spits acid at them. The three escape from the dragon, but are unaware Snoutlout on Hookfang, who waited for them to leave, followed them at a distance Snotlout approaches the island himself, stating if he wants something, then he will take it.
After returning the egg, Astrid, Hiccup, and Fishlegs are in the Great Hall, searching in the Book of Dragons for a dragon that fit the description of the one that attacked him. Eventually, they conclude the dragon that laid the eggs was a Changewing. After a while, Tuffnut enters the hall, holding a Changewing egg, which he still believes is a 'Stone of Good Fortune.' Astrid tries to take the egg from him, but Tuffnut doesn't allow this, and tells the group he got it from Snotlout. The three investigate, and discover Snotlout went to the island and stole multiple Changewing eggs. With a crowd gathered around him, Snotlout auctions off each egg, selling the last one to Bucket. The group tries to reason with Snotlout, but he remains vain and selfish, and states he doesn't care, as he is now rich. He leaves, unconcerned the 'Stones of Good Fortune' were actually Changewing eggs.
The scene changes to Ruffnut and Tuffnut, who stand on a ledge, with Tuffnut holding his Changewing egg, and preparing to jump into a pit of Fireworms, believing the "Stone of Good Fortune" will prevent the Fireworms from burning him. As he jumps into the pit, Stormfly catches him and saves him from the Fireworms. Returning to the ledge, Hiccup tells the twins the stone is a Changewing egg, and Tuffnut describes a Changewing dragon, before pointing out one that is camouflaged behind them. The dragon attacks, and two others join him. After hitting Tuffnut into a tree, the Changewings snatch the egg and fly away as a group. Hiccup and Fishlegs observe the Changewings that attacked them were the mothers of the eggs. Since they worked together to take Tuffnut's, they were likely leaving to go find more and wouldn't leave until all of them were safe.
In the evening, the teens warn Stoick the Changewings will lay siege to the village until they find their eggs. Gobber enters the room, telling them the 'Stones of Good Fortune' were actually Changewing eggs, and he always got the two mixed up (Implying he may have seen a Changewing egg before). A Changewing dragon exits a house, chasing a villager. More dragons appear and attack the village in search of their eggs, and Hiccup tells his father to evacuate the inhabitants of Berk, while he and his friends help the Changewings find their eggs. After they think all the eggs were found, Hiccup arrives and tells Stoick the evacuation isn't needed anymore. They spot the Changewings, accompanied by a fourth, creeping down the dock towards the ship. Fishlegs realizes a fourth egg is hidden on the ship, and instantly suspects Snotlout. Furious, he tells the others to go hold off the Changewings, while he goes and gets the egg.
Fishlegs boards the ship, and confronts Snotlout. Although at first he is perfectly calm, mocking Fishlegs as usual, Snotlout quickly becomes frightened as Fishlegs explodes with rage, tears and digs through Snotlout's things and corners him against the railing of the ship. Fishlegs darkly tells Snotlout he can make fun of him, and mock his knowledge of dragons, but he'll never permit him to separate a baby dragon from its mother. Bucket and Mulch, who observe this, advise Snotlout to give Fishlegs the egg. Meatlug finds the egg hidden under a basket. Fishlegs grabs it, and angrily tells Snotlout he's going to take the egg. Terrified, Snotlout doesn't protest. He leaves to return the egg.
Walking into the deserted village, Fishlegs finds himself surrounded by four Changewings at the front door of a house, however, they don't harm him, as he holds the egg. Fishlegs talks to the dragons, and tells them he is going to return it, and if they spare him, he'll make sure nobody ever steals their eggs again. One dragon takes the egg from him, and the others rears up and seemingly lunge at Fishlegs. When Fishlegs closes his eyes and shields himself, the Changewings mysteriously disappear and he faints.
The next day, Hiccup draws the Changewing in the Book of Dragons, with Fishlegs correcting him on various mistakes, and advising him to draw their teeth, as well as the dripping acid, taking pride he saw the dragons up close. Fishlegs talks about studying the Changewing so they can learn more about it, and Hiccup adds on they should train one. Gobber calls Fishlegs, and pairs him for a training session with Snotlout. The episode closes with the two confronting one another with shields as Hiccup does the closing narration.
"Having courage isn't the same as having no fear. It's about being afraid and pushing forward anyway, whether that means saving a baby dragon, protecting those you love, or giving a special someone the butt-kicking they so richly deserve."
- Jay Baruchel as Hiccup Horrendous Haddock III
- America Ferrera as Astrid Hofferson
- Christopher Mintz-Plasse as Fishlegs Ingerman
- T.J. Miller as Tuffnut
- Brook Chalmers as Viking Farmer
- Tom Wilson as Mulch
- Chris Edgerly as Gobber the Belch
- Lucas Grabeel as Gustav Larson
- Julie Marcus as Ruffnut/Lersen
- Nolan North as Stoick the Vast
- Zack Pearlman as Snotlout Jorgenson
- Tim Conway as Bucket
- This episode features the Changewing.
- In the movie, there was an image of a Changewing in the Dragon Manual, but in the episode, the book does not have a sketch, as no Viking had ever successfully examined it.
- The Changewing dragon may be featured further throughout the series, as Hiccup becomes interested in finding and training a Changewing near the end of the episode to further learn more about it.
- It is said by Stoick that for the first time, the inhabitants of Berk have never retreated the island to anything.
- Ruffnut references the events in "Race to Fireworm Island" by saying "You (Tuffnut) remember what just one of those things (Fireworms) did to you?"
- This is the first time in the series that Fishlegs shows Berserk qualities, like his book counterpart.
- Fishlegs was the only one to come face-to-face with four of the Changewings and was able to describe their physical appearance to Hiccup at the end.
- This is the first episode in which Meatlug reveals the qualities of a dog-keen sense of smell and digging up objects.
- The Changewing eggs glow and change color, as if it were a crystal ball.