The second book in the Unicorn Rescue Society has Elliot and Uchenna, just made freshman members of the society a day ago, travel to Basque Country to try to find (and rescue) a missing dragon.
This was a perfectly fine book for the target audience. There was some action and adventure, a little humor, and chances for the characters to both mature and do the right thing. There's an interesting twist also, where we find out that their eccentric mentor had once mentored two other children, only to be tragically backstabbed by them later.
So it's perfectly fine for the reader it's aimed at, but just "perfectly fine" is kind of a disappointment. The first book had a lot of clever wordplay and humor, this book's comedy and word use felt like the writer had gone down the well-trod roads of 'kids will get it, kids will (probably) laugh'. I know humor is subjective, but I felt the first book was appealing for a wider audience, and making the reader think as well. Also, the last book had the main characters being proactive all the time, especially in the conclusion. In this book they get jerked around a lot. And they help in the climactic rescue, but half (or more) of the rescue is done by somebody else that pops into the scene just out of the blue. Again, not awful (and certainly fitting the age group), but it could have been better!
The first book was surprisingly clever, this book feels like it was cranked out to meet a sales deadline. I might take a peek at the third book, but unless the reviews are stellar I'm likely not going to bother.