"Everybody has lost something they thought they couldn't live without. Sometimes to find it again you have to be willing to do anything, even look fear right in the eye... just make sure you don't blink."
Stoick, Gobber, and Hiccup embark on a search for Trader Johann as Johann is overdue to it's annual visiting to Berk. Hiccup doesn't know what exactly Stoick wants from Johann as he only is only told to find Johann and nothing else. After hours, Stoick decides to turn back to Berk, and is upset. Gobber tries to cheer him up by reassuring him that whatever Stoick wanted from Johann will arrive safe and sound, Hiccup watches as his father is still disappointed.
Hiccup then decides to find Johann himself alone to brighten up his father. In the morning, as he prepares supplies in the satchel attached to Toothless. However he is jeopardized as Astrid hears him about their journey and finds him preparing supplies, Snotlout then follows also as he hears his name and takes the salmon from Hiccup. Hiccup confesses and reveals to them his plans to find Johann's special item for his father. Astrid asks to join, but Hiccup tells them he needs to go alone as his father might get suspicious, but he eventually lets them to come but reminds them strictly not to tell the other Riders about it.
However, Snotlout disobeys mockingly as they embark on their mission with Fishlegs and the Twins joining altogether. Moments later, Astrid spots something floating down at sea, they are shocked to find Johann unconscious, just floating by with a piece of his ship. Hiccup and Toothless rescues Johann and rest on a tiny island.
As soon as Johann regains consciousness, he is deeply traumatized of what happened to him, as he repeatedly says 'the fog'. Hiccup asks Johann whereabouts of his ship, Johann responds that he has no idea of what happened to it, as he explains that he was only sailing towards sea as usual, until suddenly, he claims his ship was being torn apart and pulled out. Hiccup is confused, but Johann tells him that when he was trying to make up time as he is 3 days overdue at his schedule, he got too close on the feared territory of the archipelago, Breakneck Bog.
Fishlegs tells them that many ships have sailed to it's territory and only few have been heard to have barely return. Astrid says that her grandfather claims it's overrun by pirates, but Snotlout denies that as he explains that many people claim the place to be haunted by the legendary Fog Monster, where Tuffnut and Ruffnut explains it to Fishlegs hauntingly, that the creature makes a creepy moan to its unsuspecting victims, then it attacks by surrounding its victims and scrapes the skin off their bones, it then drops the bones as rain from the sky after finishing them.
Trader Johann quickly accepts that claim, because he witnessed the creature 'surrounding him'. Hiccup tells Johann that he desperately needs to find his ship as he explains that there's a special item for his father. Johann admits there was an item but tells him it wasn't for Stoick but for Hiccup. Hiccup is confused, but Johann is confused also that Stoick didn't tell his son yet, as he reveals the item was from her long-lost mother. Hiccup is stunned ominously, he asks what was in it. Johann has no clue as he never really saw the item, as it was already placed inside a chest with a Berk crest imprinted on it. Hiccup's desire to find it increases after hearing that and asks Johann to come and guide them to Breakneck Bog where his ship first disappeared.
But Johann is traumatized and refuses in fear to go back, he even threatens them with a knife in his boot, but admits he doesn't actually have a knife nor any weapon. Hiccup just accepts his decision, he just asks Johann how can he get to Breakneck Bog. Johann tells them to head east and find a group of islands shape like a man's hand, the island that looks like a thumb is Breakneck Bog. Before they leave, Hiccup assigns Snotlout and the Twins to take Johann back to Berk, Snotlout protests, but Hiccup tells him they don't have a choice and if anything bad happens he claims Snotlout will be glad the Twins are there to support him. Therefore, Hiccup, Astrid, and Fishlegs, whose terrified, embark on their journey to Breakneck Bog.
A while later, Hiccup, Astrid and Fishlegs manages to find Breakneck Bog and heads straight to the thumb-shaped island. Meanwhile, the Twins and Snotlout, who reluctantly accepts his assignment but admits it to be lame, escorts the frightened Johann back to Berk. Meanwhile, Hiccup, Astrid and Fishlegs have flown all over the island and has no success to find Johann's ship, not even it's remains. Just then they hear a strange noise that startles the dragons and Riders, and they decide to check it out despite Fishlegs' dismay. On foot, Fishlegs stumbles upon hundreds of leftover bones and becomes increasingly frightened, just then, as Astrid walks on, Stormfly becomes cautious and then manages to pull Astrid away from being crushed by a plummeting anchor.
By that, they discover Johann's ship resting atop a tall tree. The Riders attempt to land on the ship, but discover the ship cannot hold the amount of weight of the dragons, so the Riders are forced to scavenge the item by themselves while their dragons stand guard down below. However, as soon as they are about to begin their search of the chest, a bone shower pours down on them, and they quickly seek shelter down below the ship's deck. The Riders are beginning to be creep out, especially Fishlegs. Suddenly they then heard scraping up top causing Fishlegs to be increasingly terrified of his surroundings, but Hiccup just tells them to press on and find the chest quickly. While searching, Fishlegs is startled by a hand bone touching his shoulders and screams in fear, but fortunately, Hiccup finally finds the chest. Suddenly, heavy footsteps begin to descend on them and they are force to hide behind a storage room, closing the doors, and Hiccup telling them not to breathe.
But the creature is about to open the doors, and once it opens they yell but shock to discover it was only the Twins and Snotlout making fun of them. Astrid rages in anger and tackles Tuffnut by beating his head with the hand bone used on Fishlegs earlier repeatedly, while Ruffnut also takes a turn of beating Fishlegs. Hiccup tells them to stop, he then asks Snotlout why would they do all that, Snotlout responds that it was payback for assigning him to escort Johann back to Berk. Hiccup asks where is Johann, Snotlout reassures him that he's fine. In truth, Snotlout and the Twins abandoned Johann in the middle of the sea.
Suddenly, the ship begins to tremble unable to hold after all the activities occurring and falls down the tall tree, the Riders brace for impact but luckily survived the crash. When Hiccup asks their condition, they hear something coming after them and makes a break for it, but are confronted by the Fog Monster. The creature fills the lower deck with a thick mist, making the Riders panic. But the fog settles and disappears, but not before taking the chest with it also. Frightened, most of the Riders decide to quit the mission and head home. Though Hiccup lets them to return as he intends to find that chest alone, Astrid tells the other Riders to help Hiccup out, but the Riders are unconvinced, until Astrid puts them in Hiccup's situation by asking them what if the chest was from their mom.
The Riders paused after hearing that, and eventually they rejoin having a change of heart but with some reluctance, Hiccup is greatly thankful for their support, and begins their search for the Fog Monster. Moments later, after a struggling search through a mist they find the Fog Monster, whom moves in a very unusual way. When the Riders are about to catch the creature, it splits itself into two. Astrid, Snotlout and the Twins follows the other Fog Monster while Hiccup and Fishlegs follows the other one.
The Riders fails to capture the creature, but discovers they were only luring the Riders, as a huge thick fog approaches them, and in a similar way to Johann, surrounds them. The dragons suddenly then hover above and flap it's wings to remove the thick fog and revealing the Fog Monster, is actually dozens of small new dragon species witnessed by the Riders.
The Riders wonders what are they as they can see this type of dragons breathing smoke instead, Fishlegs answers it that they are Smothering Smokebreath dragons which stuns all of them, especially Snotlout, as Fishlegs already knew these dragons. Fishlegs explains that he in fact read about them but did not believed they existed prompting him to believed there is an actual Fog Monster. Hiccup just tells the Riders to stop the argument, and asks what does he know about these dragons. Fishlegs give out their characteristics, that these dragons hide under a veil of smoke and very territorial, but Fishlegs couldn't recall the last one.
The Smokebreaths attack in all directions making it nearly impossible for the Riders to escape. Hiccup decides to fall back, as he orders the Twins to create a path for them by letting Barf and Belch create a huge blast, warding off the Smokebreaths. The Riders finally manages to reach a safe distance, but for Hiccup it's not yet over, as he will not leave without the chest. Snotlout tells him he doesn't even know he has it, but becomes a doubt, as they spot the Smokebreaths lifting the giant anchor into a cave.
Hiccup and the Riders spy on the cave in a safe distance, Hiccup asks for any more info he'd like to share now, Fishlegs recalls the last one he didn't mentioned about the Smokebreaths, he tells them that the Smokebreaths are desperate for metal objects as they'll use it for constructions of their nest, acting as defense against bigger dragons or others they fear as a threat. Hiccup uses a telescope, that Tuffnut actually brought with him from the ship, to take a closer look inside. He sees the Smokebreaths welding the metal objects for their defense and spots the chest lying safely for now.
To get inside, Hiccup devises a plan to lure the Smokebreaths with Snotlout's metal necklace, that Snotlout has been wearing throughout their journey that he also obtained from the ship. Snotlout acts as the bait for the Smokebreaths by calling them and exposing his necklace to them, the Smokebreaths take the bait and charges on Snotlout, taking the necklace and himself also. The Smokebreaths begin to return to their nest. Hiccup almost has the chest but the Smokebreaths discover them. Hiccup is about to be devoured by the Smokebreaths' thick mist, but luckily Toothless wards them off. When Hiccup and Toothless begins to leave, Snotlout, while still wearing the necklace, is being welded and attached to the other metal objects. Hiccup and Toothless rescues him and Snotlout gets a lift.
The Smokebreaths are gaining up on Toothless, Hiccup tells Snotlout to let go of the necklace, which he does so in reluctance. The Riders altogether flee but with the Smokebreaths in pursuit, to force them to turn back, Astrid tells them to throw any metallic object they have at the Smokebreaths, it proved effective as the Smokebreaths head home with all their metallic loot. However, one Smokebreath refuses to leave as he spots the metallic leg of Hiccup and grabs it, causing Toothless tail to scramble and making them plummet down. Fortunately, Fishlegs and Meatlug painfully tackles the Smokebreath away from Hiccup, saving them. The Riders finally head home.
Hours later at Berk, Snotlout and the Twins' dragons help Johann's severely damaged ship to be carefully land down to the harbor as it undergoes repairs. Stoick asks Johann if he needs anything else, Johann has one request, to be left alone 5 minutes with Snotlout and the Twins who was responsible for abandoning him in the middle of sea, and he exclaims it in anger.
Moments later, at their house. Stoick lets Hiccup open the chest, with some hesitation. When Hiccup opens it he finds inside a doll-stitched Nadder that he quickly remembers, Stoick explains that the doll was made by his mother when Hiccup was only an infant, but Hiccup reacted terrified by it causing him to not sleep for a week. Hiccup is stun to learn that he was greatly afraid of dragons when he was young, Stoick then tells him that one day, when they were going out fishing, Hiccup's mother tried to give the doll again to her son but Hiccup still reacted scared and threw it away in the sea. Hiccup asks his father how'd he managed to retrieve it, Stoick explains it showed up on a fishing net, and was traded to Johann, thus contacting Stoick.
As Hiccup watches and holds the doll, he reveals after her loosing her mother when he was little, Hiccup was starting to fear to forget her, but with the dragon doll made from her now in his hands again it now acts as a reminder to Hiccup of his mom, and comments he loves the gift. Stoick tells Hiccup that it would finally pleased her mother to finally hear that from her own son.
Later at his bedroom, Hiccup keeps the gift at the hollow of his bed's headboard to symbolize the moments Hiccup had with her mother. Toothless then nudges for a night time flight at the full moon, while Hiccup realizes he conquered his fear of dragons that became his best friend, and the two enjoy their flight throughout the night of the full moon.
"Most people are afraid of things because they don't understand them. For me, it was Dragons. Then one day that changed, and my greatest fear became my best friend."
- Jay Baruchel as Hiccup Horrendous Haddock III
- America Ferrera as Astrid Hofferson
- Christopher Mintz-Plasse as Fishlegs Ingerman
- Julie Marcus and T.J. Miller as Ruffnut and Tuffnut Thorston
- Chris Edgerly as Gobber the Belch
- Michael Goldstrom as Trader Johann
- Nolan North as Stoick the Vast
- Zack Pearlman as Snotlout Jorgenson
- The Smothering Smokebreaths appear for the first time in this episode.
- This is the second time that Hiccup's mother is mentioned in the series. The first time was a brief moment in How to Pick Your Dragon.
- Toothless has the red tail with the skull Gobber made for him despite it being destroyed in the previous episode, though one could argue that Hiccup just made a new one.
- This is the first time that Toothless has been seen hovering without Hiccup.
- It is revealed that when Hiccup was a baby, he was afraid of dragons and the exact reason was not revealed until the second movie.
- The toy dragon given to Hiccup resembles a Deadly Nadder with four legs.
- Toothless seems to be able to fly without Hiccup in this episode, though the regular position of his tail could just be for hovering.
- After they rescued Trader Johann, they talked about a fog monster. You can see that Hiccup's green tunic doesn't reach to his mid-thigh but is shorter for a moment.
- When the teens come to Breakneck Bog the dragons are walking behind them, but in the very next shot they are gone.
- When Hiccup, Astrid and Fishlegs are below deck on Johann's ship, we can see small windows but when they show the outside of the boat in other scenes there aren't any windows.
- When Stoick tells Johann they're glad he's safe the Smothering Smokebreaths' voice can be heard.
- The fish Snotlout eats looks more like a tuna.