As the Travelin' Nine head to Chicago, the team is filled with hope and optimism. After a disappointing loss in Cincinnati at the start of their baseball tour, the heroes of the Spanish-American War bounced back in Louisville. Doc and Woody came through with timely fielding, Crazy Feet and Tales smacked clutch hits, and champion horses provided that extra kick, helping the barnstormers to their come-from-behind victory.
Griffith, Graham, and Ruby's father passed away in the war. And now they must join their mother and their father's wartime traveling baseball team, The Travelin' Nine, on a a tour of America to raise money. No one will tell the kids why the team needs money so badly. Their only clue is a baseball with a hole the size of an acorn in it that their Uncle Owen gave to them the night of their father's funeral. When all three kids hold the ball, strange things begin to happen.
The year is 1899, and the Travelin' Nine are crisscrossing the good ol' U.S. of A., raising money to pay off the Payne family's big-league debt! As the team heads into the River City, Griffith is beginning to realize that there's more at risk than meets the eye, something beyond the need to raise money: something involving the ball that could put his entire family in danger.