In Colorado gathering data for Ken's dad about an old lawsuit between two ranchmen over water rights, Ken and Sandy find every move thwarted, every action watched.
THE BLACK THUMB MYSTERY
Ken and Sandy prove the innocence of a banker who has been found guilty of conspiracy in a robbery. The boys track down many clues before they discover the motive behind the sinister plot.
THE CLUE OF THE MARKED CLAW
Vacationing in a fishing village on Long Island, Ken and Sandy play an unexpected part in the capture of a dangerous ring of smugglers.