Hiccup's sister

There is was again. Every time Liv would sing a tone, something would repeat it back in a faint whistle. Setting down her basket of herbs, she decided to investigate, following the whistles to their source. Little did she know that what she would find, would change her life forever. TITLE SAYS ALL. This is Hiccup's older sister. Starts in the 1st movie then will continue to the 2nd