Jimmy Valentine is an inveterate gangster and his specialty is cracking safes (especially those in banks!). Once out of prison, it isn't long before he's "at it" again, and police officer Ben Price is determined to catch him in the act. While planning his next hoist, Jimmy falls in love with the banker's daughter and decides to reform. He writes a letter to an old prison buddy and explains that he is "bequeathing" him his burglary tools since he's decided to go straight and stop his "trade." He even opens a shoe store in town to make a modest but decent liviing.
While at the bank of his future father-in-law, Jimmy witnesses a scene where two little girls are playing and one encloses the other in a newly patented vault which won't open before a certain time. The mother is hysterical as she is afraid her daughter will run out of air before the vault opens. Jimmy happens to have his "toolbox" with him, and he doesn't hesitate to break open the vault and save the little girl, even if it means he gets "found out" and has to go back to jail. Ben Price is at the door to intercept his suspect, but when he sees that Jimmy has had a true change of heart, he decides to "let him off." He even pretends he doesn't recognise him, then strolls away.