*SPOILER ALERT*
I have always enjoyed the CHERUB series, despite the books going downhill in the last few. However, I was expecting a lot from Shadow Wave. However, there is no big mission to end on, and half the book is spent telling you the story of Kyle, not James. There was the question posed before it was released "Will James Adams survive?" but there was never any real tension in the book and James was never really in a life or death situation. What's more, the blurb seemed to indicate a tough moral decision for James whether to side with Kyle or CHERUB, but the decision was easy and was made without a second thought, seemingly.
In short, the book lacked a mission and enough time on James, the supposed main character of the stories. It was nice having some of the reminiscing about earlier events, but this could not make up for what is a very lacklustre book which failed to deliver a satisfying conclusion to James Adams's story.
Read it if you wish to complete the series, but do not expect much at all.