«Jasper Penzey: International Boy Detective: The Ruby Brooch of Atlantis» by Monica LaSarre

Jasper Penzey has never known his mother and his father never wants
to speak of her. At the ripe age of 9 years old, on the eve of his and his
father's move from Louisiana to Santorini, Greece, precocious Jasper
discovers an amulet and a note from his mother. So begins the journey
of a lifetime into island life, complete with a traipse through history and a search for the location of the lost city of Atlantis. What starts out as a
summer of fun tagging along with his history professor father, quickly
turns into a romp through all things Greek with a host of new friends and an undercurrent which pulls Jasper into searching for his mother.

At his side throughout his search for Atlantis is his new friend Cally.
Together they learn that dodging men who are following you can be scary;
that ice cream is a perfect pawn for negotiating with those who stand
in your way; and how to trust in the help of friends and family. Jasper
discovers how heart-wrenching it can be to leave behind the only home he has ever known and how to make friends in a new place where everything
seems foreign. He also learns that the love of a mother can come from
unlikely sources, a blessedly welcome fact for a boy who is grievously
missing his own.
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