Telephone company worker Grover Cleveland Alexander (Ronald Reagan) makes his hobby a profession when he's recruited to pitch for the Philadelphia Nationals, the beginning of a storied 20-year career with only a 200-game loss. And through it all, Alexander's dedicated wife (Doris Day) sticks by his side when he's called to duty in World War I; struck by a mysterious affliction; tempted by the bottle; and traded to various ball clubs.