"Someone's embezzling major league money from the minor league Bayport Blues, and retired baseball great, manager Stuart Murphy is the prime suspect. He wants the Hardy Boy's to clear his name--and as a sign of good faith, he gives them a vintage baseball card valued at $100,000!
But the boys face a dangerous lineup of hoods and henchman who want the card at all costs. The game is heating up fast, and every pitch is down and dirty. Frank and Joe are right in the line of fire, and they'll have to come out swinging--or risk becoming the ultimate victims of foul play!"