Gerald is a boy born out of wedlock, and into misfortune. His mother, Samantha Andrews, is a poor woman living in a mobile home who collects ceramic dolls as a hobby. She meets Gerald’s father, Edward Lamtet, a doll maker, and they fall in love. Samantha gets pregnant, but unfortunately, unbeknownst to Samantha, Edward is already married, leaving Samantha to raise the child, Gerald, by herself. With Samantha being too proud to accept support money, the Edward sends Samantha a "Number 1" doll.
Gerald has trouble growing up. He is slightly mentally challenged due to being dropped on his head at birth, by the inebriated on-call doctor. Gerald has few friends other than a neighborhood girl, Helen, and his mother’s eclectic friends; a clueless lush named Ethel, a mother-hen-like transvestite named Dolly, and the straight-and-narrow Kate. Gerald is a good boy, and although not very athletic, he loves bowling.
At about age 30, Gerald has been working at the Bowling Emporium for several years. Helen is still a neighbor, and Samantha plays poker with her 3 friends every Friday night. One day Samantha learns that Gerald’s father has died, and that the doll maker’s son is positioning his company to be sold. She realizes she can now provide more for Gerald, because the doll she was given is a valuable "Number 1" doll, and all the “Number 1” dolls are needed to sell the company. That night, she plans to tell Gerald and her friends about the doll’s origin. Instead, Samantha unexpectedly dies and never gets to tell anyone about the doll and its value.
As a way to cope with his loss, Gerald decides to have his mother cremated and her ashes put into her favorite doll (the “Number 1” doll). Gerald takes the doll, and mother, with him everywhere. One day, he takes her to the laundry mat, and someone steals the doll while he is not looking.
The police have little interest in searching for a lost "doll". So, Gerald takes it upon himself to find his mother. He puts up fliers of his mother as the doll. He checks the laundry mat every day, to the annoyance of the clerk. In spite of his failures, Helen helps Gerald set up a fundraiser at the Bowling Emporium to raise enough money for a private investigator.
At this fundraiser, we learn that Gerald can actually take care of himself, financially at least, because he is an excellent (pro-level) bowler. However, he injures his foot and must go to the emergency room, where ironically he sees a little girl with his mother’s doll, or so he thinks. Gerald confronts the girl and discovers that there are many of the same dolls. The next day, however, Gerald gets an anonymous tip that allows them to track down the doll maker, only to find out that the doll maker has passed away and that the son of the doll maker is about to sell the company, along with all the “Number 1” dolls, within the next couple of days. They make an appointment to visit with the doll maker’s son.
Mother’s doll has “mysteriously” re-appeared at the doll company’s museum. During the meeting, the son ignores Gerald’s request for the doll back and continues to prepare for the sale of the company, pushing it up to the next day. Neither Gerald nor the son put two-and-two together to realize that they are brothers, although, Helen sees an uncanny resemblance. Gerald is desperate, and with the help of Helen and friends, decides to break into the toy company after closing, and steal mother and her ashes back.
That night, Gerald, Helen, Dolly, with two of Dolly’s leather-clad friends, break into the building and make it to the museum, passing by security and avoiding the son, who is in his office speaking with his lawyer and assistant.
As Gerald and the gang are attempting to exit the building with the doll, the son and his group find Gerald trying to get through the warehouse, and a fight and a chase ensues. The chase ends at the end of a wall of boxes in the warehouse where the son pulls a gun and insists on getting the doll back. At this point, the son’s assistant, who was his father’s assistant since day one, finally tells everyone the story about Gerald’s mother and how she came to own the "Number 1" doll. Everyone, to the son’s dismay, realizes that the son and Gerald are brothers. The lawyer also realizes that this makes Gerald part owner in the company, due to a flaw in the doll maker’s will. This leaves Gerald very rich and more importantly, the owner of the doll which contains his mother’s ashes.
But Gerald does not forget his roots once he is rich. He marries Helen; still works at the Bowling Emporium, although he now is the owner; and everyday, Gerald’s mother watches over him come and go from her perch by the door.