The Dragon Riders are suddenly awakened when they hear a loud horn warning them that there is a Screaming Death attack. However, Snotlout and Astrid argue with each other of who's going to the Great Hall and the Armory. To settle this, Snotlout confidently challenges Astrid and Stormfly to a race to the Great Hall, and Astrid agrees. But the two quickly fight each other with their dragons and tear up the interior of the Great Hall. Stoick is furious that it was only supposed to be a clean Screaming Death attack drill, but the Riders actually destroyed the entire village (technically it was only the Great Hall). Hiccup apologizes, but Stoick and Gobber aren't satisfied with their apologies and Stoick decides to punish their behavior.
Stoick orders the Dragon Riders to clear out Mildew's rotting cabbage field by the end of the week to ensure that the harvest is going to be settled. While Hiccup assigns Astrid to clear out the boulders, Snotlout interrupts that it should be him to do it, Astrid reluctantly agrees. It seems that the clearing seems to be going in good progress such as Ruffnut and Tuffnut eating away the dirt with Barf and Belch, and Fishlegs feeding Meatlug a bit of the delicious rocks that they were suppose to clear out. It quickly goes downhill, when Astrid and Snotlout both argue again and somehow their dragons quickly start a fight, Hiccup and Toothless barge in to end the feud. But Toothless too goes in rage and joins in the frenzy, Hiccup orders their dragons to fly on the other side. The argument continues and Hiccup asks what exactly happened, their opinions are both considerable and Hiccup just asks them if they can work together, they both disagree and finally end the fight. Fishlegs informs Hiccup that he feels that Stormfly and Hookfang's behavior was unnatural because they would always stay out of their business.
Later that night, Stoick asks how did the teens first day of clearing the field go. Hiccup lies and tells Stoick that it was going fine, but Stoick knows that Astrid and Snotlout are turning the 'catapult' at each other. A loud knock is heard twice. Astrid and Snotlout demand Hiccup to not let them work with each other. Hiccup responds that he'll figure something out tomorrow. Stoick asks Hiccup if there's a problem, Hiccup lies again and tells Stoick that everything is fine for a brief moment, but finally lets go of his anger and says that Astrid and Snotlout are driving him insane. He feels a bit better after venting. Stoick explains that there are three ways to deal with this situation, but the first two involves giving them weapons and let them fight to the end, permanently ending the problem. Option three is a more efficient way, it works by tricking Astrid and Snotlout into working together.
The next day, Astrid and Snotlout unknowingly meet at each other in the field and both know that Hiccup tricked them. They both agree to prove that neither one of them is not the problem. Hiccup gloats a bit that his plan is working like all great leaders do, but great leaders are also often proven wrong when Astrid and Snotlout's dragons start fighting again. Afterwards, they gather at the Dragon Academy, and Hiccup tells Astrid and Snotlout that their dragons have picked up the two's animosity. In order to settle this, Hiccup swaps Astrid and Snotlout's dragons and they can get to know at each other's dragons for a day. The twins also want the day off as they desperately convince Hiccup to give it to them, but he ignores them. Later, Snotlout is enjoying Stormfly's blazing speed and firepower. Meanwhile, Astrid is amazed at Hookfang's firepower, and she later discovers Hookfang's new ability that involves him strongly flapping his wings and creating a powerful wind burst that can blow a large tree for miles. Snotlout also discovers Stormfly's new ability by patting Stormfly's head once and causing a single spine shot that fires perfectly straight, with perfect accuracy. Both Snotlout and Astrid have a great time bonding with their opposite dragons.
Hours later at nightfall, the two return and seem to have enjoyed their time getting to know each other's dragons. Hiccup is sure the two will finally mend their differences tomorrow. The next morning, Fishlegs and Meatlug investigate at the cabbage field by looking for clues of what cause Stormfly and Hookfang's unnatural behavior. Meatlug digs out the dirt at where the feud started and they discover a hidden truth that Fishlegs suspected all along.
At the Dragon Academy, Astrid and Snotlout are about to secretly feed their dragons, but find their dragons' pens destroyed and Stormfly and Hookfang have escaped. Fishlegs informs the Dragon Riders that Stormfly and Hookfang are both quarreling at the exact same spot at the cabbage field again. Astrid and Snotlout suggest they both enter the feud and try to calm down their dragons. Hiccup discovers Fishlegs discovery in this kind of field, a growing Dragon Root, the exact opposite of Dragon Nip that instead makes dragons enraged, which catches the twins interest. Astrid tries to calm down Stormfly but her attempt fails and Snotlout's too, they ignore their Riders and Snotlout asks Astrid how to calm their dragons. Astrid has an idea and Snotlout agrees, they both ask their dragons if they want to tear apart at each other they're going to have to get through their riders, Stormfly and Hookfang finally slowly calms down and is now retrained to their respective rider. Hiccup and Fishlegs sees the moment to take out the Dragon Root but Hiccup and Toothless are unable to, fearing that Toothless will go angry when he gets near. But Meatlug's rock diet causes her to be immune to the effect of the Dragon Root, but while they talk Barf and Belch comes near the Dragon Root and has taken effect of the Dragon Root, Ruffnut and Tuffnut are unable to control their dragon. Fishlegs closes into the root and attempts to rip it off while Hiccup and Toothless cover Fishlegs' back.
But the Dragon Root proves difficult for Meatlug to rip it off and requests more dragon strength, Astrid and Snotlout swap their dragons again to control their dragons when they get near the Dragon Root. Barf and Belch continues to rage across the Dragon Root in an attempt to stop them, Astrid first uses Hookfang's new ability to temporarily stop Barf and Belch and pushes the Dragon Root more but still sticking to the ground. Barf and Belch closes in, Snotlout then uses Stormfly's new ability and finally breaks the roots of the Dragon Root with a clean spine shot. As Meatlug carries the Dragon Root away, Toothless pulls Barf and Belch away from the Dragon Root. Hiccup tells Snotlout and Astrid that they can cooperate as a team and mend their fences only by themselves and not depending on someone to control their behavior and attitudes.
Hours later, Astrid and Snotlout are getting along quite well in the field and they even ask each other to teach them their dragons' new abilities that they discovered earlier on. Hiccup and Stoick watch this and are glad that the positive side of option three worked, and the riders continue to clear the field and prepare it for the town's annual harvest.
- Jay Baruchel as Hiccup
- America Ferrera as Astrid Hofferson
- Christopher Mintz-Plasse as Fishlegs Ingerman
- T.J. Miller as Tuffnut
- Chris Edgerly as Gobber the Belch
- Nolan North as Stoick the Vast
- Zack Pearlman as Snotlout Jorgenson
- Andree Vermeulen as Ruffnut
- Toothless - Night Fury (Hiccup's Dragon)
- Stormfly - Deadly Nadder (Astrid's Dragon)
- Meatlug- Gronckle (Fishlegs's Dragon)
- Hookfang - Monstrous Nightmare (Snotlout's Dragon)
- Barf and Belch - Hideous Zippleback (Ruffnut and Tuffnut's Dragon)
- The title comes from the book A Tale of Two Cities.
- The advice Hiccup gets is similar to How to Pick Your Dragon. Astrid gives Hiccup "the honey and the hatchet" for Stoick, that he knew about; and here Stoick gives Hiccup "option 3" for Snotlout and Astrid, which she knew about.
- This is the first time Meatlug has carried two people.
- Dragon Root is introduced.
- Despite it was only Astrid and Snotlout that destroyed the Great Hall, Stoick made all the riders clear the field. This might be because it was the entire group's idea to run the drill.
- Though Ruffnut and Tuffnut have beds, seen in Twinsanity, they prefer to sleep upside down.
- This is the first time Hiccup has called himself a great leader.
- Hiccup is revealed to occasionally be guilted into admitting the truth, especially when he's trying to lie to his father.
- Hiccup is shown to sometimes pat himself on the back when he does a good job.
- In this episode we have seen two hidden abilities of the dragons for Nightmare have Wing Blast and Grounckle are Immunity of Dragon Root.