Frozen Fever (Jelsa)

Elsa and Kristoff are preparing a lavish surprise birthday celebration for Anna. However, Elsa gets a cold, which causes her powers to "wreak a little havoc".
A mysterious young man about Elsa's age appeared out of nowhere and helped Elsa by making her plan/surprise work for Anna's Birthday .

A/N:
This isn't what you expected. Okay it's a jelsa book. If you don't like Jelsa, don't read this.