Warm and alluring, yet deceptively deadly, Melody Island lures wayward Viking and dragons to its beautiful beaches, before the siren-like Death Song seals their fates in a shell of amber. Sunlit beaches. Clear waterfalls. Fresh fruit. Melody Island offers everything a travel-weary Viking or dragon could desire before falling prey to the tropical isle's resident predator, the Death Song. Both colorful and cannibalistic, the Death Song entices dragons onto Melody Island with its lethal lullaby and then traps its unfortunate, hypnotized victims in a thick amber cocoon so that it can feast on them at a later time. As they race to the edge, the Dragon Riders must overcome temptation, tune out the Death Song, and flee Melody Island before they become part of its enthralling mystique—forever.
Following Dagur's escape from Outcast Island, Hiccup and the other Dragon Riders found this island when their dragons heard a strange call. They then made camp for the night. However, their dragons except for Toothless, were then captured and cocooned by the Death Song. While searching for their dragons, the Riders had a brief encounter with a wild Thunderdrum named Earsplitter before discovering the Death Song and its lair that is filled with cocooned dragons. Everyone except for Hiccup was captured, and he work alongside Earsplitter in freeing the others, including Earsplitter's son, by igniting Monstrous Nightmare gel that have been poured all over the cocoons.
The Riders returned to the island, so the baby Death Song, Garffiljorg could be raised by the adult Death Song. This time they came prepared, by making sure that the dragon's song couldn't reach their dragon's ears and bringing the prototype for Inferno with them so that the fire from coated Monstrous Nightmare gel blade could free them from the dragon's amber.