Summary.  Ben Bones arrives on the river bank, and is trying to force all the local clubs to band together into his Great Club of the River.  Our boys resist this of course.   His motive is that he is one of three nephews named in the strange will of Abner Doody, who lives in the Red Castle mansion and estate.  The will stipulates that the nephew with the greatest number of friends will inherit the whole estate.  The other two nephews are Joe Doody and Howard Swift.  They join the F&S Club, and resist the Great Club of the River.  Howard Swift’s mother is Abner Doody’s sister, and Joe Doody’s deceased father was Abner Doody’s brother.  Ben Bones’ father had married Joe Doody’s widowed mother, making Ben Bones and Joe Doody step-brothers, but Ben Bones is not a nephew of Abner Doody.  Abner Doody dies, and the race is on to gather friends before the 30 day deadline when the winner of the estate will be determined.  There are many twists and turns in this race, but Doody prevails and inherits the estate.  He shares it equally with the Swift family, who take him in as one of their own.  Ben Bones is exposed as a fraud.  Lots of caves and ghosts and mysteries as usual.