Between the Sea & Sky by Jaclyn Dolamore
Description (from GoodReads):
For as long as Esmerine can remember, she has longed to join her sister as a siren, the highest calling a mermaid can have. But when her sister runs away to the mainland, reportedly to elope with a human, Esmerine is sent to retrieve her.
Using magic to transform her tail into legs, she makes her way unsteadily through the streets of New Sweeling. There, she will come upon a friend she hasn’t seen since childhood – Alandare, a boy, now a man, who belongs to a winged race of people. Together, Esmerine and Alandare put aside their differences to find her sister, and in the process discover a love that cannot be bound by land, sea, or air.
I’ve been in love with the description of Dolamore’s sophmore novel and I’m so glad to say that I might be even more in love with the cover!