The film takes place in the English countryside at the cottage of a somewhat wealthy old woman named Mrs. Bramson (Whitty), an invalid who lives there with her niece Olivia (Russell) who also happens to be employed by the dowager. For some reason Bramson is cranky and verbally abusive towards Olivia. So of course Olivia resents the old woman's attitude and feels trapped and bored with her position so she acts less than kindly towards her.
Mrs. Bramson discovers that someone has attempted to hide some pieces of broken china in one of her flowerbeds. She soon realizes that it was her maid Dora (Tottenham) that was responsible and confronts her about it. The maid explains that she hasn't been herself since meeting her new boyfriend, who she plans to marry but can't get him to actually commit to a date. Dora asks Bramson if she could speak to him on her behalf and the old woman acknowledges that she'll " deal with him ".
The rest of the film is very suspenseful as Danny waits for an opportunity to gain access to the old woman's safe and steal her money, and Olivia is first repulsed by, then finds herself becoming strangely attracted to the charming rogue. All the while trying to determine whether he is responsible for, or even capable of committing the recent murder. Time after time our attention is drawn back to the mysterious hatbox and its possible grisly contents.
If you're a Hitchcock fan you'll probably enjoy this film. There's not much action. but there are extra helpings of tension and suspense to go around.