“She Said OK,” this week's episode of “Girls,” felt more than it has in the past like a show for adults. Maybe it was Hannah's landmark 25th birthday, maybe it was Gaby Hoffman all grown up and mentally ill, maybe it was Shoshanna smoking a cigarette, maybe it was the Smashing Pumpkins.

Or maybe it's that “Girls” is beginning to share with its audience a self-awareness about the narcissism and selfishness in some of its characters, like Marnie, who really is turning into a monster. She co-hosts Hannah's birthday party -- which Hannah's parents paid for, a detail Marnie doesn't advertise, just as she wants to keep the free drink password (“banana”) a secret from the minions. It's a perfect situation for Marnie: She gets the credit for doing something for someone else when it's really all about her. She tells Hannah that the party will be a great opportunity to post some Instagram photos that Charlie will see; and of course, she chooses a venue with a stage.

But first: Adam lets Hannah cut his hair, and before she can finish, he gets a desperate call from his emotionally unstable sister Caroline (a game-changing Hoffman), who has been ditched on the side of the road by an abusive boyfriend. Adam tells Caroline she can regroup at their place but there is no chance she can stay with them – apparently Caroline tried to euthanize their grandmother once, and is permanently banned as a houseguest.

Hannah, clearly a bit clueless about Caroline's destructive history, is more sympathetic to Adam's sister, and invites her to her birthday party. The venue is divided into two rooms, which allows for a handful of individual storylines to unfold simultaneously. It works. After insulting the birthday girl about her appearance, Marnie leads Hannah through the space, where they greet ancillary guests as a queen would her court. It's off-putting, and so is the way the supposedly “best friends” treat each other. Shoshanna marvels at how little the other three have accomplished in four years, and Marnie selfishly ignores Hannah's insistence that she does not want to reprise their duet of the show tune “Take Me or Leave Me,” which they sang together on Hannah's 21st birthday. And Hannah's editor David, who wasn't invited to the party, bursts in – clearly off his head – and makes a spectacle of himself, demanding a glass of cold water and an iPhone, so he can troll for a date on Grindr.

Ray is anxious about seeing Shoshanna, but shows up to the party anyway, after he's had a bit of a career boost (and he's anxious about that, too): The owner of Grumpy's, who is sick with an undisclosed but apparently terminal illness, has given the reins to Ray. At the bar, he gets chummy with a guy who turns out to be Shoshanna's date. Later, he goes outside to speak to her, and it's as awkward and terrible and forced as he feared it would be. After assuring her that his life is on the right track, Ray tells Shoshanna that he can't be friends with her, and she barely reacts.

Back inside, Ray is alone in a corner, rocking out to “Today” by the Smashing Pumpkins (because he's over 30 and knows who they are), but his reverie is cut short when the DJ changes the song to one David requested. He confronts her, insisting that she broke the “contract” they entered into when he requested his song: “It's not fair to end things in the middle!” He's talking about the song, about Shoshanna, about his boss's life. And he's talking like someone who doesn't fully grasp the passage of time, who has been waiting for someone or something to jump-start his life for him. He takes out his anger on David, and Marnie and Hannah's duet is cut short when the audience gravitates to the other room to see the real show.

Adam and Hannah have never been more in sync, but there's a sense of foreboding creeping around the edges of their bliss. On the way home from the party, Adam gives Hannah her birthday present: A chain with one of his baby teeth as a pendant. Well, it's either his or Caroline's, since their mother kept them in the same box. Either way, it's his “genetic material,” he tells her – and it's clear that in his mind that it represents a bond as strong as blood.

Speaking of blood, Hannah and Adam's romantic night is cut short when Hannah goes in for a quick visit to the bathroom to find Caroline, naked from the waist down, holding up a glass. When Hannah asks her what's she doing, Caroline breaks the glass in her hand, leaving Adam and Hannah to clean up her mess.

Last week, I worried that Jessa might get in the way of Hannah and Adam's relationship, which seems to flow along quite comfortably as long as it exists inside in a bubble. And that bubble is hard to protect from the prickly kind of company Hannah keeps. But now it looks like Adam's genetic material might be the one to burst it. Hannah is at her best and most compassionate when she's in love with Adam, but her compassion is opening a door that Adam wants to keep closed. If that door opens, it might reveal to both of them that Adam's desire to care for Hannah is a little too close to pathology for comfort.