One forbidden love. Two broken hearts. Three little things.

Hattie Waltz should forget the troubled neighbor leaving for boot camp in 1917. He forgot about her ages ago. It had always been the Waltzs verses the Kregers, his family pitted against hers. When she hands him a farewell gift, a chemistry lesson unfolds. The good kind.

Arno Kreger can't leave Iowa or his old man fast enough. He's eager to prove his worth on the battlefield and stop blaming himself for his brother's death. Before entering the train, he bumps into Hattie. He's loved her forever, always from the sidelines, because nobody crosses Hattie's pa.

One innocent letter soon morphs into many. Arno and Hattie share three little secrets in each letter and grow closer together. But he's on his way to a war across the ocean, and she's still in her father's house. Their newfound love will need to survive dangers on both fronts.