Plot
In New York City, Sonny Koufax is a 32-year-old slacker and law school graduate who has not taken the bar exam, works one day a week as a toll booth attendant, has his food delivered by his friend Nazo, and lives off a $200,000 compensation from a minor accident. His girlfriend Vanessa threatens to break up with him unless he takes more responsibility.
Sonny's roommate Kevin Gerrity proposes to his podiatrist girlfriend Corinne before he leaves for China to work on a case for his law firm and she accepts. She vehemently dislikes Sonny because he constantly teases her about her former job at Hooters to put herself through podiatry school.
The next day, Sonny wakes up to find Julian "Frankenstein" McGrath, a five-year-old from Buffalo, New York left at their apartment. A note states that his mother is no longer able to care for him after falling ill and that Kevin is his biological father. Sonny contacts Kevin, who is puzzled by the news.
Despite his selfishness and lack of parenting skills, Sonny assures him that he will take care of Julian until Kevin returns from China. To win Vanessa back, he introduces her to Julian. However, Sonny discovers that she is now dating Sid, whom—despite being much older than her—she reveres as more motivated and intelligent with a "five-year plan".
Becoming frustrated with parenting after a few days, Sonny poses as Kevin and takes Julian to his social worker Arthur Brooks telling him that Julian should return to his mother. However, Arthur informs Sonny that Julian's mother died of cancer and offers to place Julian into a foster home. Unwilling to allow Julian to be placed in a foster home, Sonny agrees to keep Julian until a family can be found to adopt him.
After this, Sonny rants about it in a phone call to his father Lenny, who is shocked and infuriated with him for trying to raise a child, due to his irresponsibility. Sonny decides to raise Julian his own way. They develop a strong bond and Julian helps Sonny find a new girlfriend in Corinne's lawyer sister Layla. Arthur finds a family for Julian and leaves messages for Sonny, but becomes concerned when he does not respond.
After a meeting at school where Julian's teacher complains about the habits he has developed due to Sonny's influence, Sonny rethinks his parenting methods and adjusts both his and Julian's behavior. Days later however, Arthur reveals he has found out Sonny impersonated Kevin and threatens to have him arrested if he does not hand over Julian. Sonny reluctantly complies, although Julian is hurt that he has to leave. Sonny contacts Layla to help plan a case regarding Julian's future.
In court presided by Judge Healy, Layla, Kevin, and Sonny's lawyer friends Phil and Tommy represent Sonny, while his friends and even Corinne provide positive testimony and tell Judge Healy he is a suitable father. Layla also has Julian testify as well and he provides information regarding his birth in Toronto before moving with his mother to Buffalo, which sparks Kevin's memory. Sonny then calls himself to the stand and asks Lenny (who is visiting from Florida) to question him.
Despite Lenny's fervent belief that he is not father material, Sonny convinces him that he will not fail at being a father. His words touch the men present in court, even Arthur and his prosecution team, who all contact their own fathers to express their love for them. Impressed by Sonny's sincerity, Lenny and the whole courtroom vouches for Sonny to raise Julian. This is interrupted by Judge Healy [a] who still believes that not only should Sonny not get custody of Julian, he should be also be sentenced as well for defrauding the city and orders her bailiff to remove him.
However, Kevin (now able to explain that he is Julian's father) admits to Corinne that Julian was the result of a one-night stand with a Hooters girl when he and Sonny flew up to Toronto during the 1993 World Series. He apologizes to her, and insists that Judge Healy drop the charges. She grants Kevin custody pending a DNA test much to Julian's dismay but Sonny promises Julian that although he cannot be his father, he will always be there for him and still considers him part of his family. After Kevin is confirmed to be Julian's biological father, Sonny passes him to Kevin, and the two start to bond. Sonny still maintains contact with Julian through Kevin, often meeting up with him for activities such as basketball.
One year later, Sonny has completely turned his life around. He is a successful lawyer, is married to Layla, and they now have a child of their own. Sonny is given a surprise birthday party at Hooters by his friends with Kevin, Corinne, and Julian in attendance. He is then surprised to see Vanessa working there as a waitress with Sid working as a cook, revealing that his "five-year plan" did not go as she had hoped.
