From Edgar Award Winner Dori Hillestad Butler comes a new chapter book mystery series, The Treasure Troop Join Marly, Sai, and Isla, three code-cracking kids on the hunt for an old neighbor's hidden treasure.

In the third book of this code-busting series, Marly, Sai, and Isla are back on the hunt Mr. Summerling has left them a brand-new set of clues to follow, including tickets to the mysterious Summer Island. So with tickets in hand, our trio sets off to their late neighbor's island. Can they finally discover what lies at the end of this treasure hunt?