- "After joining Astrid’s auxiliary dragon riders, Spitelout started to think of other ways he could help protect the archipelago. Thus was born Storehouse Island: A secret cache of emergency supplies to be accessed in case of an attack on Berk. But in true Jorgensen fashion, Spitelout settled Storehouse Island without first checking with its natural inhabitants — the incendiary Singetails."
- ―Hiccup's Map from Race to the Edge
Storehouse Island is the ideal place to build a storehouse, apart from the raging Singetails. Relatively flat, it is a rather small land mass with a smaller piece broken off its west. It is dominated with lush green conifers.
Dragons: Race to the Edge
Spitelout and Kingstail discovered the island a month before the events of "Turn and Burn" and saw that it would be perfect for an off-site location for a Berk storehouse. Instead of returning to Berk to inform Stoick, Spitelout decided to build the storehouse on his own. At first, Spitelout was able to build it, however he soon discovered a Singetail dragon had appeared on the island and started setting fires. Spitelout tried to fight it off in defence for the storehouse, and set a trap hoping to catch it.
For over a month, Spitelout and Kingstail fought the Singetail. He then received help from Stoick, Skullcrusher, Hiccup, Toothless, his son Snotlout, and Hookfang during the events of "Turn and Burn". When Spitelout informs the others that the Singetail has been setting fires all over the island, Hiccup concluded that it was marking its territory. Though soon, more Singetails arrive, and the group realizes that the fires were actually signals for reinforcements. Realizing that they cannot fight off all of the Singetails, the group abandons the island and the storehouse.
It's assumed Spitelout was later able to reclaim the island from the Singetails and rebuild the storehouse in "Not Lout", which earned him great praise from the people of Berk.
It is revealed in the episode The Wings of War, Part 2 that Singetails still live on Storehouse Island, even more than before. Hiccup comes here to study the Singetails and find their weaknesses. Spitelout also came on the island for revenge. He named all the Singetails there. He manages to trap one of them, Deathlout, in a net.