Zack Brown, portrayed by Seth Rogen, and Miri Linky, played by Elizabeth Banks, are long-time friends and roommates living in Monroeville, Pennsylvania, a suburb of Pittsburgh. Their friendship dates back to their first grade days, but life hasn’t been kind to them lately. With Miri stuck at a local shopping mall job and Zack serving coffee at a nearby café, they have fallen behind on their utility payments. As Zack spends countless hours enthralled by his passion for the Pittsburgh Penguins and his participation in the amateur hockey team known as the Monroeville Zombies, the pair finds themselves without water just as they prepare to attend their high school reunion.
At the reunion, Miri catches the eye of her dashing former classmate, Bobby Long, while Zack strikes up an unexpected conversation with Brandon St. Randy, a gay porn star who happens to be Bobby’s boyfriend. Returning home, the situation worsens as their electricity gets cut off, plunging them into deeper financial troubles. An interesting twist occurs when a viral video surfaces, featuring Miri caught in an embarrassing moment at Zack's workplace, leading him to suggest they should create a pornographic film to make ends meet—taking advantage of the increasingly mainstream acceptance of adult entertainment.
With a team of friends and collaborators in tow, they embark on an ambitious project: a Star Wars parody titled Star Whores. Producers line up, and Delaney, one of Zack’s colleagues, manages to rent film equipment and a studio space. However, returning to the studio after a long night of shooting reveals a devastating setback: it's being demolished, and their vital equipment is gone. Inspired yet undeterred, Zack finds a hidden camera at his workplace which he intends to use to resurrect their project, pivoting the film’s theme to Swallow My Cockuccino, a coffee shop-oriented adult film.
As the film takes shape, the line between friendship and romance blurs between Zack and Miri. When the time comes for their on-screen sexual scene, it turns unexpectedly tender and genuine rather than transactional, reflecting the deep bond they've formed throughout their journey. That evening, their apartment utility services are restored, courtesy of their supportive cast and crew who throw them a party to celebrate the completion of their film.
During the party, tension arises when another actress, Stacey, expresses interest in Zack, leading to a misunderstanding that challenges Miri’s feelings. This culminates in a pivotal scene where Miri insists on filming with Zack just as planned, creating a rift when Zack feels betrayed by the suggestion that Miri might be okay with him being with Stacey. He realizes that their connection was far more meaningful than he had thought when he confesses his love to Miri, only to be left heartbroken by her silence. In a fit of anger, Zack quits not only the project but his job, leaving Miri behind.
Months later, with the unfinished film haunting him, Delaney approaches Zack, who is now working at Mellon Arena. Delaney manages to entice Zack back to help finish the film, leading to a heartfelt reunion where Zack learns that Miri never went through with her scene with Lester. He pours out his feelings, and to his joy, Miri reciprocates his long-suppressed love.
In a heartfelt conclusion, we learn that Zack and Miri have tied the knot, launching their own video production company, Zack and Miri Make Your Porno, creatively crafting amateur videos aimed at couples, showcasing their unique bond and shared passion for their craft.
