Twelve-year-old Marnie Price thought losing her grandfather was the hardest thing she'd ever face-until a mysterious crossword puzzle shows up in the mail, followed by a cryptic note, and eventually a key. Suddenly, Marnie is unraveling a trail of secrets left behind by the man she adored: a former World War II codebreaker whose past is far more complicated than anyone knew. With help from her cousin Mel, her brother Nick, and a classmate who may know more than he's saying, Marnie begins decoding clues that lead her to a decades-old betrayal, a hidden operation called August Rain, and a secret that could change her family-and the country- forever.

Set against the backdrop of grief, growing up, and a junior high production of Macbeth, this is a story about courage, truth, and the quiet strength it takes to speak up when it matters most. Maybe, just maybe, it's also about finding hope, like an August rain, when you least expect it.