His first published foray into explicitly sexual material, it tells of a series of erotic and violent encounters in a small American seaport following the arrival of an African-American sea captain.

[1][2] Peter Nicholls in The Encyclopedia of Science Fiction described the work as "serious in intent, though likely to be shocking to most readers in its evocation of the extremes of sadomasochism in imagery which is sometimes poetic and often disgusting -and so intended- perhaps as a Baudelairean ritual of passage".

Equinox concerns the sexual and violent encounters, "the search for erogenous gratification of a diverse collection of people",[5] that take place when an unnamed black sea captain docks his 72-foot boat the Scorpion at a small American seaport.

At his studio, Proctor tells the Captain the story of his life in picaresque episodes, culminating in his first encounter, many years before, with the bewitching Catherine.

In the novel's closing movement, the perpetrators of a sex crime are protected by their corrupt friends, while the innocent vagabond Robby is lynched in their place.