lost-chapter
Explanation
The Joke
The comic is a meta-promotional piece by Zach Weinersmith about the book "Open Borders" (a graphic novel about immigration policy co-created with economist Bryan Caplan). Zach explains that he and Kelly have been working on a popular science book called "Soonish," and mentions that the book "Open Borders" contains a "lost chapter" that was cut from the final publication. He teases the audience about this lost chapter, saying it is about how nuclear fusion works, and invites readers to check it out.
The comic functions as both a genuine advertisement for the book and a humorous aside. Zach acknowledges directly that the comic is promotional ("This bonus comic brought to you by..."), but wraps the promotion in his characteristic self-aware humor. The "lost chapter" concept plays on the idea of deleted scenes or bonus content that fans of any media eagerly consume, applying it to a nonfiction graphic novel about immigration economics.
The Humor
The humor is lighter and more self-referential than a typical SMBC strip. The comedy comes from Zach's candid, slightly awkward self-promotion -- he knows he is shilling his book within his own comic, and he leans into the discomfort rather than hiding it. The casual tone ("Hey gang, its Zach!") contrasted with the weighty subject matter (nuclear fusion, immigration policy) creates an endearing mismatch. The final panels showing potential nuclear fusion reactor designs add a layer of genuine scientific interest that rewards readers who clicked through expecting just an ad.
References
"Open Borders: The Science and Ethics of Immigration" is a 2019 nonfiction graphic novel by economist Bryan Caplan, illustrated by Zach Weinersmith. "Soonish: Ten Emerging Technologies That'll Improve and/or Ruin Everything" is a 2017 popular science book by Zach and Kelly Weinersmith. The lost chapter about nuclear fusion relates to energy technology content that was part of Soonish's scope.