Peter Lends A Hand

Hector Warmington, a prosperous jeweller, is substituting faked jewellery for the genuine articles sent to him by his clients. This faked jewellery is made by William Haydon, who is wanted for murder. Warmington has evidence to clear Haydon but prefers to keep him under his thumb and his scam going. 

Three boys see mysterious smoke signals out on the moors and follow them to discover Haydon's hiding place. Aided by Haydon's stepson, Harry, the boys must unravel the jewellery plot and clear Haydon's name.