In the town of Mammoth Falls, a group of boys keep things lively with their madcap schemes. In various chapters, they create a sea monster and rile up all the vacationers by sailing it about on the lake; find the loot from an old bank robbery in a Civil War cannon; win a hot-air balloon race; create a mysterious flying man (mannequin) to confuse everyone during a parade; and rescue a downed Air Force pilot while fending off the rival gang.

It was entertaining. I read it several times when I was a kid, so when I found a copy somewhere, I determined to reminisce.