After too many vodka tonics at her best friend's baby shower, twenty-seven-year-old Sasha finds herself having a ladies' room epiphany. How quickly life can change, she thinks to herself: one minute she's writing a master's thesis about a TV comedy show for kids–and the next, the program actually gets optioned with her as the star. But Sasha’s awe at the twists of fate proves to be premature. The real shock comes the next day, when her routine visit to the ob-gyn reveals that she’s pregnant—even though she hasn't slept with anyone in more than two years.

To her unbelieving ears comes the doctor’s diagnosis: Sasha’s body has unwittingly hosted a cellular hitchhiker, a medical anomaly known as “lazy sperm.” And now that this plodding genetic contribution has finally fulfilled its destiny, it will be up to Sasha to summon the courage to revisit her past loves even as her future slowly takes shape inside her. Which of her exes will be the father and how will he take the astounding news? And what will the end of the mystery mean to Sasha? The answers are revealed in this wonderfully inventive debut about the bonds that linger between people even after they part ways, and how the future can change in the twitch of a tail.