The Siren's Apprentice (Sirena's Children Book 2)

After the twisted events of Halloween, Cassie wants nothing to do with her siren kin. When a strange boy shows up at her school, however, she is inevitably pulled deeper into their world. Not only is David Turner a siren, he's supposedly her future mate. New complications arise during the next full moon. The power of the Blood Moon running through her veins acts up, causing her and Sirena to unleash something from the darkest depths of the ocean. A malevolent sea daemon that should only exist in myths and legends. It brings with it promises of death, destruction, and the downfall of Cassie’s entire world.
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The Siren's Apprentice is the second book in the Sirena's Children series.
#1 - The Ocean's Call
#2 - The Siren's Apprentice
#3 - The Lunar Artifact