The Other Hofferson

Ingrid Hofferson, Astrid's twin sister, has a terrible secret. She is in love with the village screw up, Hiccup Horrendous Haddock. But when Hiccup finally seems to prove himself to be a true Viking by shooting a Night Fury out of the sky it seems that things will change. Only when Hiccup makes a dangerous call Ingrid finds herself learning more about dragons and the boy she loves.
And she'll have to make the most important decision of her life; betray Hiccup and Toothless, or keep their secret and betray her village and everything she's ever known.