'This story...has for its background one of those innumerable golden, sandy beaches that are found in so many places around the thousands of miles of the great Australian coastline. It is the sort of beach where Australian boys and girls go regularly to spend their holidays, and in this book we read of all the fun and adventures that five children can have on such a holiday.
'On this particular holiday, the five "McHams", as they call themselves, made up of three Hamiltons and two McGees, decide to rebuild for their own use an old derelict boatshed. But there they strike trouble. What is the mystery about the old boatshed? Why does a very evil-looking man so obviously want them out of the way? There is action, suspense, and quick thinking on the part of the two families, before the mystery is finally solved.'
(from Dust Jacket).