On its surface, "Greasy Lake" is a story concerned with one night in the lives of three teenage buddies out of school for the summer, cruising around their small town, feeling pretty dangerous and looking for excitement. By the time the night ends, they have found more trouble than they had anticipated and enough excitement to last a lifetime. The narrator, who tells the story in retrospect, remembers they also behaved in disturbing ways they could not have imagined when they set out for the evening. The events at Greasy Lake include a violent fight, an attempted rape, an escape into the marsh, an underwater encounter with a corpse, and the destruction of the narrator's car--which doesn't belong to him.
The story works on a deeper level, however. It is an initiation story in which the narrator grows up during the course of one night. Telling the story in the voice of a mature adult, the narrator makes clear the distinction between the irresponsible boy he was at the beginning of the evening and the very shaken young man he becomes by the next morning. The boys who set out thinking they were "bad characters" emerge from Greasy Lake no longer looking for adventure. When some girls show up to offer them drugs and more adventure, the narrator is not enticed; instead, he feels like crying and can't leave fast enough.