First of all, if you haven't already make sure to go back and read the other books in the series as they're all connected and this book in particular does a great job of referencing events across the entire series.
If you've gone and done that then you'll enjoy this chapter in the ongoing 'Bubble series. It returns us back to a story with the main characters, rather than the side characters that've featured in the last couple of books.
What's interesting is the author has once again come out with a different sort of time travel story, slightly adjusting things to throw in a parallel universe twist. It keeps things fresh and keeps you thinking.
Being so quick to publish means this has bang up to date real world references that work really well.
My only minor niggle is the ending just came out of nowhere! I won't say what happens, but I will say the author needs to hurry up with the follow up novel ASAP as this is really only half a story.
On the plus side he's been very consistent in putting out this series very quickly so I hope I don't have to wait too long to find out what happens next.