|類型/形式：||Code and cipher stories
|ISBN:||9780545060448 0545060443 9780545152907 0545152909|
|描述：||190 p. : ill. ; 20 cm.|
|叢書名：||39 clues, bk. 4.|
Amy and Dan are hot on the trail of the fourth Clue, but their ruthless relatives will stop at nothing to eliminate them from the competition. Their hunt leads them to an ancient city that has been a hot bed of Cahill activity for centuries. Can they really solve a mystery that has eluded their ancestors for generations?