This book is about Aisha and Walter (and their cat Fleabag) they hear that the world is ending, so they leave with Walters parents to find Aisha's long-lost sister in June.

The book and the concept were fine, I liked the idea, but I wish we got to know more. I get that it's a middle grade book, and we don't get as much depth as the biggest plot point is the world ending. You might as well let us know how and why. 
I did like the book enough to finish, but I wouldn't come back to this book anytime soon.