The Hardy boys were sons of a celebrated American detective and from their father learned the particulars of a number of unusual crimes. They were fired with zeal to bring the criminals to justice, and during their hours from school, and during their vacation days, they followed up clues they unearthed themselves — aiding their parent very materially. Stories which are absorbing in the extreme.

The rescue of an old man from a wrecked cottage and an exciting journey to a Montana gold mine, lead Frank and Joe Hardy, sons of a famous detective, into thrilling adventures with a gang of dangerous outlaws. The outwitting of Black Pepper's gang needs all their skill and nerve when they are trapped and caught in their quest for the Hidden Gold.