TimeRiders: The Infinity Cage (book 9), Paperback/Alex Scarrow

The end is approaching for the TimeRiders. In a final effort to prevent time travel destroying history, Liam and Maddie jump forward to 2070 to confront the enigmatic Waldstein and prove if he is friend or foe. The outcome is more shocking than anyone could have predicted and they are sent back to Biblical times to save the whole of humanity.