The gem holders arrive in Montliskeard Bay for Martha, however one of them, Rob Appleton, goes rogue and agrees to try and help Luke out. Tom and Nell face danger again as they meet a wolf in 'green' clothing.

Tom and Nell find their work smashed and Rob knocked unconscious on the boat. In spite of the previous attack, Nell decides to go diving again so that Luke can be reassured. Meanwhile, up at Montliskeard Place, Barnes falls foul of Martha.