Hmm, this series started off strong but this volume is just a mish-mash of YA/Sci-Fi/Fantasy tropes. It's got Hunger Games (with young people in a battle royale type situation), Star Wars (with the two robot/droids going off on their own adventure), LOTR (with a "mother stone"... one stone to rule them all style thing). Plus we get a cute baby dragon following our robot characters now. It's just too many things all at once and it doesn't add up to much more than a fun adventure.
I adore the full page splashes. The colors are wonderful.
I'm not too excited to see where this goes next. My niece is still reading Volume 5, she's a bit bored with the series as well, so it may be awhile before I read on.
Still, I would recommend this series for youngsters! I wish my school library had stuff like this when I was a kid. My comic related choices were limited to Captain Underpants and French volumes of Tintin. Perhaps a Garfield collection or two. It's really cool to have these long narrative comics, and I'm sure a kid doesn't mind how transparent the influences are to an older reader.