<p>As they continue the hunt for their missing parents who are lost somewhere in the pages of history twins Jemima and Joe Lancelot embark on their fifth time-travelling journey into the past accompanied by best friend Charlie and Max their Tonkinese cat. </p><p></p><p>Their destination is the Roman town of Pompeii which lies in the shadow of Mount Vesuvius a volcano on the verge of a devastating eruption.</p>