The Oblong Box

In the beginning I thought that this would be a detective story, something like the Dupin' stories but it wasn't. I loved the narration and of course, how it ends.

Summary: On a sea voyage to New York, the narrator of this story notices that his friend has brought, along with his wife and two sisters, an oddly shaped box. Although the narrator believes that he has determined the contents of the box to be a painting, some strange occurrences suggest that there may be something else in the box.