Mr. Summerling's Secret Code #1

From Edgar Award Winner Dori Hillestad Butler comes a new chapter book mystery series, The Treasure Troop! Join Marly, Isla, and Sai, three code-cracking kids on the hunt for an old neighbor's hidden treasure. Marly always knew Mr. Summerling as her friendly neighbor living in the big, old house next-door. Sure, he walked around with a metal detector and talked about being a "treasure hunter," but she didn't think much of it. But when news of Mr. Summerling's death arrives at her doorstep, Marly