Ghost Town at Sundown by Mary Pope Osborne

Jack and Annie land in the Wild West and explore an old ghost town where they encounter cowboys, a lost colt, and mysterious messages. As they search for the next piece of the puzzle, they help a cowboy round up his horse and avoid a gang of bandits. The siblings experience life on the frontier while facing time pressure and dusty challenges. This Western-themed adventure is full of danger, quick thinking, and clever clues. It’s a spirited ride through America’s past.