The Mask of Destiny by Richard Newsome

The life of Australian teen Gerald Wilkins changed forever when he inherited twenty billion pounds and a mystery to solve. In The Mask of Destiny, Gerald believes his enemy Sir Mason Green will be put in prison for murder. Instead, Gerald is accused of murder himself. He’ll have to find the last of three emerald caskets to clear his name. The search takes him, Ruby, Sam, and Mr. Fry to Paris, Rome, Athens, and Delphi. They discover Delphi once held the greatest treasure on earth. It could still be there, waiting to be found by someone good. Or evil…
 
Anthony Horowitz fans will love the extreme adventure, exotic locals, and illustrations in The Mask of Destiny, the rollicking conclusion to the Archer Legacy trilogy.