The hero of this 'ripping yarn' is Michael Fitton, master's mate on the 12 gun cutter Curlew. England is about to be invaded by a force of about 14,00 men comprising frenchmen and some irishmen.(this is the 'Black Legion of the title) Some of these are regular forces and others are a motley crew which includes released prisoners. They are led by an American,Colonel,later General Tate.
As the book progresses, Fitton does his best to defeat the diabolical Tate and I leave it to the reader to discover who triumphs. Not a difficult task I would think.
It is an easy and undemanding read and one to fit into the odd idle moment. Quite an entertaining story for all that. ( )