I was rather surprised to discover that this little mystery story has a war setting in the background, and in fact the war seems to play a major role in the story. A family (minus the father, who is a soldier, as were most men his age at the time) goes on a holiday to a beach side cottage where they meet an apparently obnoxious young boy who does not like company. However one of the girls manages to befriend him and discovers that he is full of secrets that he is happy to reveal to those he trusts.
His name is Ben, but he calls himself Smuggler Ben namely because he fantasizes about being a smuggler. It is sort of one of the childhood things where we dream of the adventure without realising that the adventure involves getting on the wrong side of certain people. However Blyton's adventures always involve bad people (and there is generally no ambiguity about it, they are either thieves, or spies as in the case of this book, and are no doubt up to no good). Blyton is not interested in exploring the grey side of humanity, but rather helping us retain our innocence by undermining those who seek to take it away.
Obviously with the war playing in the background the loss of innocence is front and centre, and no doubt the holiday was not necessarily a vacation, though by the time this story had been written the London Blitz was over and the tide of the war was beginning to turn (no doubt due to Hitler's decision to invade Russia). However threats to the British way of life were still evident, and no doubt there were still a lot of Nazi sympathisers living within Britain as well (as is suggested by this book).
Okay, this is a children's book, and no doubt such books are not meant to have themes or explore deep issues – at the age when I was reading these books English had more to do with comprehension rather that actually teasing out ideas and issues, but then again is that not what English literature all about, attempting to comprehend what the author is telling us and trying to understand the themes and issues that the author is exploring? Bylton, despite being a very popular author (I remember reading a Blyton book while standing in the Melbourne Central railway station when a guy that was dressed like a punk passed me and cried out 'Enid Blyton, I love Enid Blyton'; another shop that I went into told me that I would have a lot of trouble finding any Enid Blyton books due to their popularity, though once again that was in Melbourne, and I had no problems at all finding them in Adelaide, something that I will have to do when I return for a little while in August), is not interested in exploring the grey side of life, but rather giving children the belief that they can fight to maintain their innocence. Then again, most of her stories involve children stumbling on crimes, rather that the children being the target of the crime. Still, the idea of the innocence of childhood is something that permeates Enid Blyton.