American Gothic involves the introduction of John Constantine, and what that meant for Swamp Thing. Essentially, Cosntantine works as a sort of plot driver for the series of stories that make up “American Gothic.”
An evil South-American magic cult named the Brujeria are using the Crisis on Infinite Earths to help them take over the supernatural arena, and as part of their plot, they began having all sorts of evil events take place across America. Constantine manipulates Swamp Thing into taking down these threats.
Eventually, it all leads to basically one big ol’ fight between good and evil, and literally the Ultimate Darkness against the Ultimate Light. There are a series of artists at work during this storyline – the standard brilliance of Stephen Bissette and John Totleben, but also impressive work from Rick Veitch and Stan Woch on pencils.
Moore handled the slow build towards issue #50 about as well as any writer has ever handled a build to a “big” issue number – this is a storyline without being a strict storyline (for most of the story, at least). The final battle in #50, though, is given all the trappings you would expect from a “big” issue, with Moore playing with the vast history of DC Comics and their supernatural characters.
Moore stayed on the title for a little while longer (and did some excellent work), but in many ways, this was the pinnacle of his Swamp Thing run.