Ambitious and driven, Alison Scott is a reporter in Los Angeles who just received a promotion to an on-air role at E!. Living with her sister Debbie and her family, Alison's life takes an unexpected turn when she meets Ben Stone, a carefree Jewish Canadian slacker who has found a niche in working on a not-so-reputable celebrity porn site with his stoner roommates. Their paths cross at a local nightclub during Alison's celebration of her promotion, where a night of heavy drinking leads to a one-night stand—complicated further by a miscommunication that results in Ben not using protection.
The following morning, as they sit through an awkward breakfast, it becomes painfully clear that they have nothing in common, prompting them to part ways. However, eight weeks later, Alison experiences morning sickness while interviewing the actor James Franco, triggering the realization that she might be pregnant. The news shocks her as she takes several tests confirming her pregnancy. She reaches out to Ben to share this life-altering news. Initially taken aback and brash, he eventually assures her of his support, although uncertainty lingers regarding his readiness for fatherhood, a sentiment that contrasts with his father’s enthusiasm.
Faced with her mother’s suggestions to consider abortion, Alison ultimately resolves to keep the baby. As time goes on, the duo decides to explore a relationship, preparing themselves for the child’s arrival. During this process, Ben awkwardly proposes using an empty ring box, vowing to get a proper ring someday. Yet, Alison feels it's too soon for such commitments, particularly with mounting pressure to conceal her pregnancy from her employers.
Yet doubts creep into Alison's mind as she observes Ben's hesitance to fully embrace their situation, compounded by witnessing her sister's troubled marriage. Debbie's husband, Pete, keeps odd hours, leading her to suspect infidelity. However, she eventually uncovers that he's merely participating in a fantasy baseball draft and enjoying solitary movie outings to escape Debbie's controlling behavior.
Their relationship ultimately falls apart, and when Ben expresses amazement at Pete's subterfuge, it leads to a heated argument during a car ride that ends with Alison kicking Ben out in frustration. After a road trip to Las Vegas with Pete, amid a psychedelic mushroom trip, Ben realizes the importance of rekindling their relationship. Simultaneously, Debbie tries to take Alison out for a night of fun, but their plans get thwarted by age restrictions at a nightclub. This collective night out elicits an emotional breakdown where Debbie yearns for her husband, leading to a reconciliation at their daughter’s birthday party.
Meanwhile, Alison’s boss capitalizes on her pregnancy for publicity, leaving Alison torn between her personal and professional lives. When labor begins unexpectedly, Alison reaches out to Ben, who faces disarray when he learns that her gynecologist is attending a Bar Mitzvah. An upset Ben leaves an irate voicemail for the doctor. During labor, Alison expresses regret for doubting Ben’s commitment, as he insists on being by her side when the others arrive at the hospital. This assertiveness alters Debbie's perspective on him.
Finally, the couple welcomes a baby girl, marking a new beginning filled with hope as they navigate parenthood together.
