Secret in the Sand

Elizabeth Jenkins is an eleven year old girl who has always wanted to solve mysteries. When her family moves to Hawaii, she finally gets her chance.
A box hidden in the sand containing an old diary leads Elizabeth and her family on an adventuresome quest for valuable, 15th century treasures. The Jenkins soon discover, however, that they are not alone in their pursuit and their rival has criminal intentions.
Who is this mysterious man, and why is he trailing them? Elizabeth is determined to find out!