In Station Eleven, the outer plot focuses on a post-apocalyptic world some twenty years after a global virus kills nearly everyone. Many of the central characters of this world regularly grapple with their sense of nostalgia for the past. The reader also sees the past, pre-pandemic world in flashbacks, where characters are suffering nostalgia for an even earlier time in their lives.
Much of the plot focuses on Kirsten, a child actress who survived the pandemic as a child. Now in her twenties, Kirsten lives with a traveling theatre company, which itself attempts to hang on to humanity's pre-pandemic past by recreating the plays, music, and stories that were pillars of that past culture, such as the works of Shakespeare.
Kirsten, however, has her own private obsession. Just before the pandemic broke, she watched the actor Arthur Leander die of a heart attack onstage during a performance of King Lear. Leander had been kind to her before his death, giving Kirsten a copy of a comic book called Station Eleven that his ex-wife had written.
Over the years, Leander's death takes on huge importance in Kirsten's mind. By the time the reader catches up with her post-apocalypse, she's obsessed with finding anything she can about Leander and his death, as well as with finding additional installments in the Dr. Eleven series that she's certain must exist somewhere. While Kirsten has a life in the present of the novel, she spends large parts of it focused on the past, exemplified by Leander and the comic book.
In flashbacks, meanwhile, both Leander and his ex-wife Miranda (the comic's author) are portrayed as being in the grip of nostalgia. Miranda's focus in drawing the comic is often on a past life, when she was happier than she had been as the wife of a celebrity (Leander). Leander, too, wishes he hadn't made so many mistakes, including losing Miranda and failing to build a relationship with his son, Tyler.