Warning: SPOILERS ahead for Watchmen season 1, episode 7.
Like its source material, HBO's Watchmen sequel warns viewers about the danger that comes with living in the past. In episode 6 "This Extraordinary Being," detective Angela Abar, a.k.a. Sister Night, overdosed on "Nostalgia," a drug the HBO series introduced. The resulting trip down memory lane revealed some key information for the overarching plot, including the true identity of a character from the original DC Comics Watchmen. It also demonstrated the danger of this drug, thus making a larger argument against obsessing over the past.
Regina King plays Abar, a detective investigating the death of her friend and chief of police, Judd Crawford. Abar acquired the pills in episode 2 from William Reeves, after arresting him for Crawford's murder. Reeves, she discovers, is her grandfather, and a former police officer from New York City. When Abar herself was facing arrest at the end of episode 5, she took the bottle of pills all at once, overdosing.
Watchmen episode 6 focused on Abar's experience living her grandfather's memories. Through the drug, she was able to experience first-hand the most impactful — and in many cases, the most painful — events in Reeves' life. The drug has a downside, however: as FBI agent (and former masked vigilante) Laurie Blake warned Abar part-way through the episode, overdosing on Nostalgia can cause the user to forget who they are.
"Nostalgia" has its origins in the original DC Comics limited series Watchmen. In the comic, "Nostalgia" is the name of a perfume sold by Adrian Veidt (Ozymandias) through his company Veidt Enterprises. The comic heavily implies that the perfume's retrospective marketing is in response to the buying market's romantic obsession with the past: a circumstance caused by the uncertainty and pessimism of living during the Cold War. After Veidt "solves" this public uncertainty through the comic's climax (an event called the Dimensional Incursion Event in the HBO series), he releases a new optimistic scent, "Millennium."
In the comic, the perfume is used as a motif to illustrate both the romantic appeal of living in the past, as well as the emotional harm this sort of rumination can cause. In HBO's television series, the message is much more overt: Nostalgia literally causes the user to relive memories, harming themselves emotionally and potentially losing their identity all together. HBO's "Peteypedia," an online collection of supplementary material for the show, includes a 2007 "advertisement" for Nostalgia that warns potential users of the adverse side effects.
In the most recent episode of the series, episode 7 "An Almost Religious Awe," the drug's creator Lady Trieu stated that the drug was her biggest failure, citing the users' tendency to relive their most traumatic moments over and over. She, like Veidt before her, urges the public to move on from the past and embrace the future.
The next episode of Watchmen airs Sunday December 8, on HBO.