The Elementals: Book III Inferno

When Rebecca is abducted in the middle of the night, the other Elementals are intent only on finding her and bringing her home to them. On discovering the identity of her captors, however, they realise that much more than just their freedom is at risk. In their struggle to cling on to their secret lives as Elementals, they are drawn into confrontation with an extremely powerful enemy. But as new friends appear to help them in their fight, an old foe lurks in the background waiting for his chance to strike.