Zoe (played by Jennifer Lopez) is a successful single woman in New York City who has always dreamed of having a family, but hasn't been able to find the right man. She decides to take matters into her own hands and goes to a fertility clinic to be artificially inseminated.
On the same day as her procedure, Zoe meets Stan (played by Alex O'Loughlin), a charming and handsome man who seems to be perfect for her. They hit it off immediately, and Zoe starts to wonder if she's made a mistake by going ahead with the insemination.
As Zoe and Stan start to get to know each other, they face a number of obstacles that threaten to tear them apart. Zoe is hesitant to tell Stan about her pregnancy, and when she finally does, he is unsure if he's ready to be a father.
Throughout the movie, Zoe struggles to balance her desire to start a family with her newfound relationship with Stan. She also has to deal with her overbearing best friend (played by Michaela Watkins), who is constantly meddling in her love life.
As Zoe's due date approaches, she and Stan must decide if their relationship is strong enough to weather the challenges that lie ahead. The Back-Up Plan is a heartwarming romantic comedy about the ups and downs of love, family, and parenthood.