Based on George M. Cohan's play from a novel by Earl Derr Biggers, a novelist encounters criminals trying to get money from a safe at an inn.
At a station Magee (Gene Raymond) finds Mary (Margaret Callahan) crying. Though it's closed in the winter, Magee goes to the Baldpate Inn and tells the caretakers that he came to write a novel in 24 hours to win a bet. They give him the "only key" and leave. At midnight he sees Bland (Ray Mayer) come in with a key and make a call about the safe. Bland holds a gun on Magee, who locks Bland in his room and calls the police. After a scream Mary comes in and says that Bland left by the window. Another man comes in, and Magee calls him Professor Boulton (Eric Blore). Magee finds the hermit Peters (Henry Travers) in his room. Peters writes to expose the evils of women. Mrs. Hayden (Erin O'Brien-Moore) comes in and asks Magee for help, saying her jewels were stolen and that money is in the safe. The professor sneaks down to the safe, and Mary asks him why. Then Magee asks Mary why she is trying to open it.
Mary asks Magee to get the $200,000 out of the safe and shows him a secret passage. Bland and Hayden (Grant Mitchell ) come in, while Mary kisses Magee good-night. When Jim Cargan (Moroni Olsen) comes in, Bland tells him that Hayden wanted to take the money he paid for the jewels. Hayden opens the safe, and Bland is shot in the arm from the window by Cargan's man Max the monk (Murray Alper). Cargan counts the money, and Bland asks for ten percent. Cargan pulls a gun and leaves. The professor clubs Cargan and takes the money; but Magee clubs the professor to take it. Magee hides the money and tells Cargan he doesn't have it. Mary says that Magee was with her and Peters. Magee tells Hayden his wife is in room five, and they follow her tracks. Bland knocks out the professor and finds the money, putting it in a stove. Peters lights a fire. Bland now demands 50-50. Cargan has Magee tied up. Mrs. Hayden is really Myra and warns Max not to double-cross her. Bland finds the stove burning. Peters tells Magee and Mary he found the money and hid it. Magee gets the money and passes it to Mary. Hayden claims he wants to return the insurance money. Myra talks about Cargan, and Max shoots her. Magee holds a gun as Peters takes Bland's gun and fires it.
Police come in, and others say Magee killed Myra. Another cop brings in Mary with the money, and Peters brings in Myra alive. Magee says it is an insurance swindle. The professor says he is an insurance detective, and Mary says that she is a reporter. Cargan, Bland, Max, Hayden, and Myra are arrested, and Magee asks Mary to marry.
This well-made detective story offers entertainment for escape but otherwise does not have much substance except the usual criminal greed for money.