Jenn and Matt are best friends from college who once made a pact. Now in their thirties, Jenn is a hopeless single, spending her days teaching "hot yoga" and running errands for her boss and Matt turned out to be her gay best friend. Unable to get over his ex-boyfriend, Matt has withdrawn into his comic-book store job. When Jenn decides to hold Matt to his promise of having a baby with her, it seems like the right idea at the right time. With Jenn untrusting of fertility doctors, and Matt boastful of being 'a guy' and able to have sex with anyone, they decide to fulfill a youthful promise... the old-fashioned way. Gayby follows the pair as they navigate the unexpected snags along the way in attempting to get their lives back on track and the trauma of preparation for parenthood.