The Flying Mermaid - Volcano Chronicles, #1.5

All Luce wants is to go home, but how can she? Since the war, her beloved city has been under an enchantment. Rivers run dry and the streets are haunted, or so they say. When she hears a rumor that the curse has been lifted, Luce writes a heartfelt letter to the leaders. It begins ten years ago, when she's thirteen-years-old and dying of a broken heart. Dying, I tell you!Luce's account takes the leaders into the cold heart of a mermaid.
To when she, and her bestie, Adu, live in a spidery, clifftop house with a tiny dog. Not even Sea Mother's magic or mermaids can hold back the war. When the world goes dark, it takes a wind magician and the strongest love of all to save her family and friends. Light up the skies, little mermaid! Can be read as part of the Volcano Chronicles series or as a stand-alone.