The Throne of Fire

Twice now I have tried to read this one. I like Riordan's other books. But I don't like this one. I read the first book in the series. I didn't love it, but I didn't hate it. So I thought I would try this again since it is at the library and I don't have to pay for it. But I just don't really like it. The interplay between the brother and sister (they alternate chapters) and the darker, more occult-ish magic just puts me off. I am giving up again.