It's 1932 and 10-year-old Yankee Irving's (voice of JAKE T. AUSTIN) favorite team -- the New York Yankees -- is playing in the World Series against the Chicago Cubs. He dreams of one day batting like his idol, Babe Ruth (voice of BRIAN DENNEHY), but his failed efforts in sandlot games only lead to laughter from the other kids. Following such a debacle, he finds an unlikely friend in Screwie (voice of ROB REINER), an acerbic, talking baseball that only Yankee can hear.
But things take a turn for the worse when the boy's mom, Emily (voice of DANA REEVE), allows him to take dinner to his father, Stanley (voice of MANDY PATINKIN), who works at Yankee Stadium. When Stanley allows his boy into the locker room to see Babe's legendary bat, Darlin, little does he realize that Cubs owner Napoleon Cross (voice of ROBIN WILLIAMS) has sent his washed up pitcher, Lefty (voice of WILLIAM H. MACY), to steal the bat to insure their victory in the Series.
When it's discovered it's missing, Stanley is fired and can't help but think Yankee had something to do with it. When no one will believe his story about Lefty posing as a security guard who chased him out, Yankee decides he must do something.
With the aid of Screwie and a young girl, Marti (voice of RAVEN SYMONE), whose dad, Lonnie Brewster (voice of FORREST WHITAKER) is a star in the Negro League, Yankee retrieves Darlin (voice of WHOOPI GOLDBERG) -- who can only be heard by the boy and his talking baseball -- and then tries to avoid Lefty as they make a cross-country trek to return the bat to the team so that his dad can get his job back.