The novel centres on Mr. Frank, a kindhearted but empty-headed worker for the Underground Railroad, where he works to help runaway slaves from the South flee to the Northern United States and then onto Canada.

[2] As time passes, Mr. Frank also learns of the corruption within the Underground Railroad itself, discovering that the abolitionists he works with are nothing more than hopeful slaveowners, convincing slaves from the South to run away from their original masters with promises of freedom, only to be enslaved once more[citation needed].

[3] It has been argued that Mr. Frank may be attempting to imitate Shamela by parodying Uncle Tom's Cabin, although this remains open to debate.

[4] It may also be the case that James Whitcomb Riley, the author of the poem "Little Orphant Annie", made veiled references to the people behind the book.

For unknown reasons, this same edition was released with a second title-page giving the full title of Mr. Frank, the Underground Mail-Agent.