In 1938, Charlie "Jolly Cholly" Grim was fired as the Cub's manager and replaced by their long time catcher Gabby Hartnett. The Cubs were in fourth place, seven games behind the Pirates at the beginning of September. Under their new manager, the team went 17-3 that month when the Pirates came to town for the final series of the year, ahead by only one and one half games.

Hartnett had several sore arms to contend with on his pitching staff. Perhaps the sorest arm of them all was Dizzy Dean's, who's owner had been struggling with pain all season. Still Hartnett had little choice but to put Dean in to pitch the first game of the series. Diz did OK, pitching eight scoreless innings, but lost his stuff in the ninth. In came reliever Bill Lee who Harnett would later recall: "cut loose with as wild a pitch as I ever saw", allowing the potential tying run to advance to third. But Lee got out of the jam striking out the last batter, getting the save for Dizzy Dean and the Cubs; the final score: 2-1.

September 28, Wrigley Field- The following day, Clay Bryant started for the Cubs, Bob Klinger for the Bucs. In a seesaw battle, Pittsburgh scored two runs in the eighth to take a 5-3 lead, but the Cubs came back with two of their own in the bottom of the frame leaving the game tied going into the ninth.

By that time it was almost 6PM and twilight had set in on the north side of Chicago. The umpires came close to calling the game on account of darkness. They were anxious to get the game in however as they would otherwise have start from scratch the following day as part of a double header as league rules required back in those days.

The Pirates did not score in their half of the ninth. In the bottom of the inning, The Cubs' Phil Cavarretta hit a deep drive to center field that was hauled in by Lloyd Waner. Then Carl Reynolds grounded out. Next up was manager/catcher Hartnett. By this time it was dangerously dark and the game certainly would be called if Harnett didn't get aboard. Now pitching for the Bucs was their stud reliever, Mace Brown. Brown threw Harnett a couple of curves. The Cubs' manager wiffed on the first and managed to foul off the second, just barely. As Brown described it years later:

When he was swinging at one of (the pitches), he just looked like a schoolboy, and I said to myself, I´ll just throw him a better one and strike him out.

Unfortunately for Brown, the thrid pitch was not a better one. Here's how Harnett described it:

I swung with everything I had, and then I got that feeling... you get when the blood rushes out of your head and you get dizzy.

He didn´t mention how he managed to see the ball let alone make contact, but make contact he did and the ball ended up in the left center bleachers. It was so dark at the time, the only players on the field who realized what had happened at that instant were Mace Brown and Gabby Harnett.

Soon everyone in the park realized what happened and half of them it seemed accompanied Harnett as he circled the bases.

That home run which has gone down in history as "The Homer in the Gloamin'" vaulted the Cubs over the Pirates by one half a game. They would win 10-1 the next day, taking the series and the pennant away from the Pirates.

The Cubs would go on to be swept by the Yankees in the World Series, but the 1938 season would forever be remembered for that pennant race and Hartnett's home run, perhaps the single greatest moment in Chicago baseball history.