Alex Neptune is back for his most epic adventure in this fifth and final instalment of the action-packed series - perfect for fans of Percy Jackson and Dragon Realm!Brineblood the pirate is back on the high seas with a dastardly plan - he's going to steal every drop of sea magic and use it to raise an all-powerful monster from the bottom of the ocean.If Alex, Zoey and Anil can't stop him, the monster could flood the entire world. Teaming up with the water dragon, they use a home-made submarine to journey deep into places no human has been before.But they have one crucial problem: Alex has lost his magic.Can he still lead his crew to victory? Or will Haven Bay - and the rest of the world - be lost for good?