There's only one way to prove the Germans are tapping the British front line - by letting them overhear a convincing-sounding message. But the rapidly changing position suddenly means their shells will land on advancing British troops.
Ahmadullah can see how the whole Gallipoli campaign was about going around - around the Western Front and around the Turks. So he wants to go round the headland at Gully Beach.
Celestine, in common with many British doctors, joins the retreating Russian Army. But she's going to be asked break her Hippocratic Oath in an awful moment of torture.
Holland is neutral. Robert goes there to try to find his wife - but finds himself in a farcical chase including a trip under the electric fence into Belgium.
Mesopotamia, now little known as a First World War battlefront. But taking a shortcut across the desert becomes a nightmare as lethal as anything on the Western Front.
Mickey meets the man who has stolen the secret of his new invention. He also meets a man who is singly going to change the war for the Signals Service. And he also meets the love of his life - promising sex, betrayal and death.