Lost in Londinium, the third book in the time-travelling adventure series, Spirits of London Wall, tells what happens to the four when they journey to Roman London. Finding himself nephew to a wealthy landowner, Marcus is thrown into prison as an impostor. Celts, Ellie and Jack, work in the market-place and live in a wooden barn with the Celtic community. Rachel, a slave-girl works in a Roman villa. A rollicking, action-packed story from the start, young readers will be kept enthralled as when Rachel and Jack go searching for Ellie, abducted by Cuthred, Rachel gets stuck in quicksand. Marcus, having saved the acting-governor's life, is made a centurion and fights in a brutal Roman war. Ellie, Rachel and Jack time travel to 101st-century Hora where they become embroiled in an invasion; they are forced into enemy spaceships by Bivillux and Grendo, rulers of Quirinus and Juno. Climaxing in a dramatic gladiator fight as the four face certain death in the amphitheatre opposite hungry lions, this book is both entertaining and educational with its translation of Latin words and explanation of Roman life in the Snippets of History section at the back of the book.