Frozen

Episode 14 of Defenders of Berk

Synopsis
Hiccup and Toothless return from a mission to find Berk mysteriously empty. They discover that the village has been overrun by Speed Stingers, a venomous non-flying dragon that has trekked across the frozen sea to Berk and driven everyone out of town. Hiccup must find a way to drive the Speed Stinger horde away from Berk.

Source
How to train your Dragon Website

Trivia

 * First appearance of the Speed Stinger.
 * This episode has the same title as the recent Disney movie "Frozen."
 * This is the first time Trader Johann is seen in Defenders of Berk.
 * This is the first time Toothless has reached his shot limit.
 * At the end, Johann give Hiccup a large bottle of ink from the colossoal squid. Johann said he would get Hiccup another bottle after Toothless accidentally broke it in Dragon Flower.