The Secret Maze: A Branches Book (the Last Firehawk #10)

Now that Tag and Skyla have found Blaze's firehawk family they would like to return home to Perodia, even if it means leaving their friend behind; but in order to find the magic that will open a new portal they must first brave a mysterious underground maze where the walls are constantly shifting--and when they do find their way home there is a deadly surprise waiting for them.