Behind Enemy Lines by Jennifer A. Nielsen

Infinity Ring bk 6. Scholastic, 2013. ISBN 9780545387019.
The Infinity Ring series continues, with this 6th book, to encourage primary students to enjoy a variety of adventures and learn something about world history as they follow Dak, Sera and Riq through time. The mission of these Hystorians is to fix the errors in history which have allowed SQ to take over, leading to the cataclysm which is engulfing their world of the future.
The book opens with its usual bump as the three heroes land in Aberdeen, Scotland during World War 11 in the middle of a German bombing raid. Unfortunately their local contact and SQuare, the device which advises them, are victims of the bombs. Sera and Dak return to their own time, thanks to the Infinity Ring to pick up a new SQuare only to be almost captured by Tilda, an ambitious and ruthless leader of SQ. In their haste to escape Tilda unfortunately returns to 1943 with them.
Their mission to ensure the Allies win the war involves helping the British convince the Germans that they are to invade Greece rather than the heavily guarded Sicily in what was known as Operation Mincemeat. For the first time the trio split up. Dak heads to Berlin and finds work as a kitchen hand in the German headquarters. Sera lands in Spain in time to help convince local spies that the secret documents the dead Major Martin is carrying are the real deal. Riq stays in London as a contact but is soon captured by Tilda who is determined to own the Infinity Ring and ensure the only winners are the SQ.
Fortunately the mission is successful and Tilda's efforts are largely disrupted.
Whilst I learnt something about this little known segment of war history, though it was the basis of the movie The Man Who Never Was, I felt that there were elements throughout the story which had me questioning the characters, plot and ultimately the writer. Whilst that might be an adult's view point it is the first book in this series that has left me feeling disappointed and not looking forward to continuing the adventure.
Sue Keane