Lumeru finally turns sixteen, but no one appears to remember her birthday! But it was all part of a surprise! But there's a mysterious letter from Miss Mortimer at Swanburne! But Lumeru simply doesn't get that it's a code! But she has to go visit the school anyway! But she can't figure out how to get there! But she figures it out! Oh look, Simon is here! Oh no, Quinzy is here!
If you're bored by this sad précis, please feel free to join the club. This was the worst of the four volumes of this I ever intend to follow. It was tedious and I was skipping track after track on the audio CDs because it was not moving the story and it wasn't entertaining, and it wasn't even funny. It was really saddening to see what began as a brilliant series devolve into a morass of tedium and mediocrity in volumes three and four. There was nothing new being added. It was like the author had decided that she was going to pen five volumes and would do so come hell or high water, and in complete disregard of the fact that there was clearly insufficient material to adequately fill them.
Nothing - I mean quite literally nothing - happened here, and I cannot recommend this. You would have better success going back and re-reading the first volume! That one was highly entertaining, and you would learn just as much new material from it as you would from reading this one, which I do not recommend.