Montmorency has a number of large scars all over his body after he fell through a roof onto a grinding machine whilst being chased by the police.
He is a master of the London sewerage system and carries out thefts using the sewers as a sanctuary and escape route from the scene of crimes.
He rents a room at a run-down boarding house (which is owned by the mother of Vi Evans who later becomes one of his close friends) for his alter ego, Scarper.
Having fallen under the influence of a Turkish drug, George Fox-Selwyn, unknown to Montmorency, is appealing to Robert Farcett to help him.
But before long Farcett and Montmorency have to return to London after Fox-Selwyn asks them for assistance in finding two Irish Separatist bombers.
Montmorency travels to America with Dr Robert Farcett on the trail of anarchists who wreaked havoc in Florence, Italy.
In the book, Montmorency is forced to stay in Patterson to lure in the criminal Malpensa, but he must pay a price to keep his family safe...