I really liked this one. Tavia and Effie are sisters, although not by blood. Tavia is hiding the fact that she is a siren, since they are feared. Effie is...perhaps something? We don't know yet. We do see the struggles they go through. Morrow does an excellent job of mapping her fantastical word on our own, with many parallels between what happens to sirens and what happens to black people in general.