Sapper 
Challenge [PDF ebook] 

When Colonel Henry Talbot summons Bulldog Drummond and Ronald Standish, it is to inform them of the mysterious death of one of their colleagues – Jimmy Latimer. At the time of his death, he was on a big job, and was travelling on a boat to Newhaven when he died. But there was no sign of any wound, no trace of any weapon when they found him in his cabin. What strikes Drummond and Standish is why millionaire, Charles Burton, would have been travelling on the same boat – arguably the most uncomfortable crossing he could choose and very out-of-character.