You’ll Never Know by Caleb Stephens

Grant Wilson has never been happier. He has a wife he loves, a home in the country, and a brand-new baby on the way. But all of that shatters when two masked men abduct his wife, Avery, in broad daylight. The instructions Grant receives are bizarre: If he wants Avery back, he must solve a series of riddles that arrive one after another—and the clock is ticking. With every piece of the puzzle more outrageous and complex than the last, Grant knows he’s playing a dangerous game. But he’s determined to do whatever it takes to save Avery’s life … even if it kills him.