Early on, Pretty Boy Floyd is pursued, shot and killed by an FBI agent, Melvin Purvis(Christian Bale). This gets Purvis noticed, and he is assigned to capture John Dillinger, who is on a bank-robbing spree. There are also a couple other well-known gangsters in the story such as Baby Face Nelson and Frank Nitti.
The two hardest parts to watch both pertain to Dillinger's girlfriend Billie Frechette. When they first meet, Dillinger basically tells her she is now his woman. She does eventually fall in love with him, and the other hard part is a cop slapping her around to get her to talk.
Overall. a very good movie. The story is well-told, and there is lots of action. Johnny Depp is especially good in the lead roll.
Content Warnings: A couple of scenes where people got shot were more gory than they needed to be. There was a scene with Dillinger and his girlfriend in bed, and a scene with her in the tub, both of which were suggestive, but neither of which showed nudity.