4.5 stars. 
 PERCY AND ANNABETH! YAY! (I knew it was going to happen, but yay!) 
 I really enjoyed this one, it wrapped up the series really well and it opened it up for the next series too (which I am really looking forward to!) 
 I loved the character development, esp for Rachel, Annabeth, Clarisse (even though we didn't really see much of her.) and Thalia (YAY! I seriously love her.) 
 Ah! I can't believe I've actually finished this series. I'm going to take a break from the world of Percy Jackson for a while to read some other things (& do some uni assignments that are due this week and next) but then I'll jump into the Heroes of Olympus series after a break.