Speaking in the second person, the speaker recalls sitting together in late summer, along with a friend of the addressee's—a beautiful and gentle woman. The group was speaking about poetry, and the speaker recalls commenting that, while each line of a poem must be extensively considered and labored over, it must also look spontaneous. If not, it's better to just do physical labor. After all, the professional classes look down on poets and think they're lazy, so it's best to at least produce poems that seem easy and effortless. At this point the woman spoke up, in a beautiful voice, and explained that women already know how much labor goes into seeming effortlessly and naturally beautiful. The speaker replied that there is nothing lovely that doesn't require lots of labor. In the past, lovers often looked to old books, which provided a precedent for their romance. Now, though, such labor feels idle and frivolous.
The topic of love causes the group to fall silent. They watch the last of the daylight disappear and then the emergence of the moon, which looks like a shell that has been worn out by the tides. Addressing the second-person listener, the speaker remembers having a thought suited only for her: that she was beautiful, that he hoped to love her in the artistic and elevated mode of past lovers, and that, though everybody had appeared happy, they have now become as worn out as the shell-like moon.