Plot summary

David Wozniak (Vince Vaughn) is a hapless deliveryman for his family's butcher shop, pursued by thugs to whom he owes $80,000. David invested in a company called NewTech with the borrowed money, whose owner was later arrested on unrelated charges. David works for his father Mikolaj (Andrzej Blumenfeld), who doesn't think very highly of him. Aleksy (Bobby Moynihan) & Victor (Simon Delaney) are David'd brothers. David approaches some bank for a loan, but none of them would lend him any money without a collateral.His girlfriend Emma (Cobie Smulders) is pregnant with his child. Emma is not happy with David as David is not involved with her life and doesn't call her for many days at a time. One day, David returns from work to find a lawyer Mark Williams (Damian Young) from the sperm bank (where he gave sperm donations 693 times and earned a sum of $24,255 during his student years) who tells him he had fathered 533 children. Due to complications at the clinic the doctor gave David's sperm, to all of his female clients. Of those, 142 have joined a class action lawsuit to force the fertility clinic to reveal the identity of "Starbuck", the alias he had used. The kids are contesting that Starbuck's right to privacy is secondary to their right to know who their biological father is.David's friend and lawyer Brett (Chris Pratt) represents him as he tries to keep the records sealed. He provides David with profiles of each party to the lawsuit: David stalks them, finding moments for random acts of kindness. He finds that one of his kids turned out to be a star professional basketball player named Andrew Johansson. This encourages him to look at the profiles of his other kids & help them in their lives. He visits his second child Josh (Jack Reynor) who is a bartender at a barista, but really wants to be an actor. So, David volunteers to take care of the Barista while the kid goes & acts in plays & makes his career as an actor. Josh is fired from his job, when the owner come by and finds David at the bar, but Josh gets the acting job.He finds the profile of a girl named Kristen (Britt Robertson) & gives her a visit to find that her boyfriend bailed on her with rent money & that she has overdosed on drugs. The hospital wants her in a rehab program, but she begs David to let her be released so that she can join her job at Bloomingdale's. David believes in her & signs the papers. The girl repays his faith by turning up for the job on time the next day.David makes it a mission to learn about the lives of as many kids as he can & takes a real interest in them & tries to help them in every way he can. One of his kids is mentally challenged, one of them is gay & a player. Taylor (Amos VanderPoel) is a lifeguard at a local pool. Brett discourages David from interfering in his kids' lives as that could lead to complications against David in the class action lawsuit. One of the kids named Viggo (Adam Chanler-Berat) learns of David's true identity as their biological father. He uses that leverage to stay with David (he even goes to David's basketball league, even though Viggo is terrible ta basketball) & makes him attend many meetings of the class action lawsuit kids, including their picnic camping day, where David gets to connect with even more of them. The picnic news of 533 kids from the same donor getting together is picked up by all the major news channels like the CNN, BBC, Fox and so on. Brett tells David that this is great news since the agency is not supposed to take any action that jeopardizes David's anonymity, and the picnic did just that. David can counter sue them for big damages.Spending time with his biological kids also allows David to be more attentive towards Emma & their brooding kid. This endears Emma to David & she visualizes having a real life with him. David decides to identify himself to the kids, but after the thugs assault him and even his father (The thugs now demand $100,000), he agrees with his lawyer Brett to sue the sperm bank for damages. He wins the lawsuit: he receives $200,000 and keeps his identity a secret.David has regrets, but after his father pays off his debt, David reveals his identity on Facebook. He goes to Emma's house and finds that she is going into premature labor. At the hospital, his baby is born, he proposes to Emma, and many of the children show up to see him.