A witch known as Skuld the Sorceress comes to Berk and threatens the townsfolk-then plunges Berk into darkness! As the citizens of Berk panic, it's up to Hiccup and his friends to try and stop Skuld and her minions! Plus a bonus short story, "Cruel to be Kind," as Hiccup and friends take their lives into their own hands and try to train Bumble the Scauldron
Hiccup and Astrid are on patrol when they see a man tied to a ship about to sail towards some sharp rocks. They save the man and bring him to the great hall. The man is shown to have a Sigil of Thunderhead Bay, old enemies of Berk since the Vallhala Wars. The man stuttering about how Skuld the Sorceress is coming to bring the Endless Night, and nobody belives him. Suddenly, Skuld appers and seemingly brings on the Endless Night. Everyone is in a panic as they enter the Great Hall. The man introduces himself as Flem, and explains that he is the last of the Thunderhead tribe, after the entire population of Thunderheads seemingly disappered after the Endless Night was cast upon them.