Hannah, a 24-year-old aspiring writer living in New York City, is blindsided when her parents cut her off financially. Subsequently fired from her unpaid internship, she seeks comfort in Adam, the eccentric actor she sometimes sleeps with when she can get him to respond to her texts. Meanwhile, Hannah's best friend and Type-A roommate, Marnie, hosts a dinner party for their bohemian British friend Jessa, who's returned from god-knows-where to move in with Shoshanna, Jessa's younger, “Sex and the City”-obsessed cousin.
Hannah reveals her “Forrest Gump”-induced AIDS phobia when she realizes Adam might not be practicing monogamy. Marnie lives in denial of her growing boredom with her long-term boyfriend, Charlie; Jessa avoids Marnie's meticulously planned day at a womenʼs health clinic, where Shoshanna confesses a humiliating secret.
Hannah meets up with her erstwhile college flame to find out how she contracted HPV, uncovering much more in the process. Marnie's art-gallery boss introduces her to a cocky artist who piques her interest, while Jessa gets a babysitting gig.
Hannah throws a housewarming party with brand-new roommate Elijah, but it's hard to move on when she's still playing nurse to Adam. Marnie gets bad news at work and a visit from her mom; Shoshanna avoids Ray at the party; and sun-kissed Jessa returns from her honeymoon.
Hannah gets unsolicited musical attention from heartbroken Adam and displeasing opinions on her writing from Sandy. Elijah questions his sexuality; Marnie makes a career compromise when her curatorial dreams are crushed; Jessa revels in married life; Shoshanna and Ray make magic; and Elijah and Marnie harbor a secret.
Hannah starts a new job doing “advertorial work” at GQ and has to make a few adjustments to fit in. Ray and Marnie clash in an on-again-off-again fling. Shoshanna displays glances with Ray and then later gets with her current guy. Jessa chats with Shoshanna as she works the clothing store. Adam has good news/bad news from a couple of casting calls.
Hannah moves to Iowa, where cheaper rent rates and the seemingly trusting nature of the locals impress her. She struggles to settle in amongst her Grad school classmates, who find her fiction work offensive and poorly written. Elijah surprises her with a visit as he has started to find New York grotesque.
Jessa and Adam become AA pals and Jessa gets into trouble with NYPD. Seems unlikely that Hannah long distance relationship stands a chance. Marnie is hitting the wall in her personal life but her singing career seems to finally going in a right direction.
Jessa gives her opinion on Marnie's new song. Shoshanna and Ray go shopping together. Desi gives Marnie news that makes her smile. Hannah writes an apology letter that doesn't go over well. Then she learns of the new things in Adam's life.
Hannah's friends try to help her through a crisis after she arrives back in the city and finds everyone has moved on with their lives while she was in Iowa. Hannah and Adam have an honest conversation about their relationship.
After Hannah gives Principal Toby some unexpected news, she runs into her old friend-slash-nemesis Tally. Marnie has an unsettling dream and later tries to work things out with Desi. Noticing business is suffering at Ray's, Shoshanna offers to help with marketing, performing some clandestine research on their competition. Elijah makes his pitch to Dill that their relationship should be exclusive.
Elijah and Loreen help Hannah with her plan to participate in The Moth Story Slam. Marnie prepares to go on tour with Desi. Shoshanna's plan for an “anti-hipster” Ray's takes off. After helping take care of the baby, Jessa and Adam have an epic fight.
Riding a wave of newfound career success, Hannah gets an assignment to write a story about a female surf camp in the Hamptons, where she meets Paul-Louis, an uncomplicated waterski instructor. Hoping to break her old patterns post-divorce, Marnie tells Ray he needs to spend more time at his own place, but Adam and Jessa’s intensity drives him out of the apartment.
Hannah provides cover for Marnie’s secret weekender to Poughkeepsie, which she hopes will help clarify an old chapter in her life. Shoshanna enlists Elijah to be her plus-one at a networking event for young professional women, where Jessa’s antics lead Shosh to reevaluate her post-college friendships.