Nick Pearson, played by Tom Everett Scott, is a successful children's book author who has always been a bachelor, until now. He is days away from his wedding to the love of his life, Sydney, played by Rachel Boston, when a teenage boy named Mason, played by Julian Feder, shows up claiming to be Nick's son. The only evidence he has is a note from a psychic that Nick had visited years ago, claiming that he would have a son named Mason.
Nick is understandably shocked and skeptical, especially since he has never been with Mason's mother and has no idea who she could be. To make matters worse, Mason is not the easiest kid to like – he's brash, sarcastic, and a little too eager to befriend Nick's fiancée. Nick's initial plan is to simply send Mason back home to LA and move on with his life, but when that proves difficult, he reluctantly decides to help Mason find his mother.
The only lead they have is the psychic, so Nick hires her to join them on a road trip to find all of Nick's ex-girlfriends who could be Mason's mother. Along the way, they encounter a variety of eccentric characters, including a deeply religious woman who insists that Mason must be sent to conversion therapy, a hippie artist who thinks Nick is a terrible person, and a former beauty queen who is still holding a grudge against Nick for breaking her heart.
Through it all, Nick learns some important lessons about responsibility, family, and growing up. He starts to bond with Mason and even begins to see him as a son, despite his initial reservations. Meanwhile, Sydney must grapple with her own feelings of jealousy and uncertainty as she watches Nick interact with his newfound "family."
The movie is a heartfelt comedy that explores themes of parenthood, forgiveness, and self-discovery. It is filled with hilarious moments, touching scenes, and a great cast of characters. Whether or not Nick ultimately finds Mason's mother, he learns that sometimes the most important family is the one you choose for yourself.
