Johann calls for help when his merchant comrades and their wares disappear mysteriously. When the Riders meet him at the Northern Markets, Fishlegs wonders if it's due to the "Curse of Tears" (which makes Tuffnut cry). Meanwhile, Astrid is decidedly searching for an idea for a betrothal gift for Hiccup, all the while avoiding his attempts to give his to her. The gang splits up, Fishlegs, the Twins and Astrid in one group and Snotlout and Hiccup in another. Fishlegs and Astrid attempt to find a betrothal gift for Hiccup but they find nothing. While in another part of the markets, Hiccup's betrothal gift is stolen by Berthel and Amos, and the two Riders chase Amos to the beach where he disappears. They soon discover where he disappeared to however when they are sucked into the sand by a Sandbuster dragon. Trapped in the underground cavern with Amos and the dragon, Hiccup and Snotlout try to figure out a way to work together to escape. Up above Toothless and Hookfang grab the attention of Astrid, Fishlegs, and the Twins. They use a treasure map Astrid had been offered as a gift for Hiccup to see if it might lead to the "Curse of Tears" treasure (much to Tuff’s dismay), which is where they hope Hiccup and Snotlout are. Astrid finally deciphers the map and the Riders crash through the roof of the cavern and save their friends and Amos. The episode ends (while Ruffnut comforts her brother) with Hiccup finally giving his betrothal gift to Astrid, and insisting she not worry about having not gotten him anything because she had already "given him the best gift in the world:" herself.
As of this episode, Hiccup and Astrid are betrothed, basically engaged to be married.
Snotlout also takes a jab at the show's name, asking who would like to race him to the Edge.
It is mentioned that Astrid knows Hiccup better than Fishlegs.
The Sandbuster in the episode is similar to the treasure-guarding dragons in the books How to Be a Pirate and How to Seize a Dragon's Jewel. Each dragon guards treasure underground. The Sandbuster is more like the Monster of the Amber Slavelands mentioned in How to Seize a Dragon's Jewel, because both dragons burrow underground, shoot glass, and drag victims into their burrows to rob/eat them.
Tuff is said to have a trigger since childhood, where he breaks down and cries whenever he hears the word "tear". However he has heard it and even said it multiple times in the past-
In "Breakneck Bog", Tuff says that Ruff slaps like a guy, and she slaps him to demonstrate. Tuff then says "I can't see through the tears."
In "The Flight Stuff", Snotlout addresses the other Riders, including Tuff, when he thinks he's about to die, and says he doesn't want any tears.