Kristoff, seeking a career more marketable than being an iceman, enrolls in a coding bootcamp in the Southern Isles, where a bitter and vengeful Prince Hans has been forced by his brothers to maintain a legacy Backbone application.
Faking a change of heart, Hans befriends Kristoff, hoping to leverage his connection to Arendelle's icing industry in order to exact revenge on the kingdom. It works, and Hans convinces Kristoff to hire him to rebuild the ice delivery e-commerce platform.
Hans' software exploits a performance vulnerability in Chromium browsers (used by the vast majority of the kingdom), causing every machine to get real hot every time a purchase is made.
Soon enough, the kingdom's climate begins to get dangerously warm, feeding a vicious cycle: ordering more ice causes the kingdom to get warmer, which causes people to order more ice, and so on.
Elsa, Anna, and the gang embark on a mission to convince all of Arendelle to switch to Firefox.