It was based on the novel Death on the Diamond: A Baseball Mystery Story by Cortland Fitzsimmons, directed by Edward Sedgwick and produced and released by Metro-Goldwyn-Mayer.

The film opens with Pop Clark, owner and manager of the St. Louis Cardinals, talking to newspaperman Jimmy Downey.

Pop tells Jimmy he's signed star pitcher Larry Kelly in order to try and seal the deal.

Kelly then arrives and flirts with Pop's daughter, Frances, who works in the front office as team Secretary, and then suits up for practice.

He then reveals to Frances that if he doesn't win the pennant, he'll lose the franchise to Henry Ainsley, and that he borrowed all the money he could just to hire Kelly.

When Kelly arrives at the team dinner, Downey finds him and tells him that Karnes is one of the biggest gamblers in the country.

In his hotel room, Kelly finds an envelope with $10,000 in cash and a note telling him that a "friend" hopes he will lose the next game.

As Kelly and Hogan ride a taxi back to the hotel after the game, one of Karnes's men shoots their tire out with a rifle hidden in the door of a nearby car, and they crash.

During the next game, against the Chicago Cubs, the teams are tied 3-3 in the 6th inning when Karnes motions one of his men to go perform some unknown order.

Later, several people and a policeman spot a stranger skulking out on the field in the dark, and thinking it might be the killer, jump him only to discover it's Crawfish, the umpire.

Then Downey confronts Karnes in his office and mockingly asks him to give him the "inside scoop" on which player is going to be killed next.

The next day, as players head for the game against the Cincinnati Reds, their wives and girlfriends beg them not to play, worried about the danger.

Warmack pitches well, and going into the bottom of the 9th, the Reds lead 4-3 when Hogan wins the game with a 2-run inside-the-park home run.

Afterwards, Hogan is celebrating by eating his usual hot dog when someone shoots off a loud firecracker outside the clubhouse, distracting everyone.

Frances tries to talk him into pitching Eddie Vernon instead of Kelly due to the danger, admitting that she loves Larry, and he agrees.

The final game, against Cincinnati, starts off a bit rough, but the team settles down and Kelly assures Pop he'll pitch his best.

Appearing uncredited in the film were a number of ex-Major Leaguers, including Bob and Irish Meusel, Ping Bodie, Ivan Olson and Pat Flaherty, plus one player who was still very much active, slugger Wally "Red" Berger.