Vada Sultenfuss has matured from the 11-year-old
hypochondriac in 1972 to a more serious teenager in early 1974. Her father Harry and his new wife Shelly DeVoto, whom he previously dated, are expecting a baby, and they all still live in the Sultenfuss funeral parlor in
Madison, Pennsylvania. To accommodate the new baby, Vada moves into her late Gramoo's old bedroom. She struggles with these adjustments, along with figuring boys out. A male schoolmate named Kevin Phillips seemingly likes her friend Judy, but Vada wonders if he likes her reciprocally. Both her father and Shelly unsuccessfully try to give her some advice regarding adolescent males. For a school assignment to write an essay on someone she admires but has never met, Vada chooses to profile her deceased biological mother, Margaret Ann Muldovan (Maggie), but has scant sources to go on, all confined to a small box. Among its contents are programs of plays her mother acted in, a passport, and a mystery paper bag with a date scribbled on it. Vada expresses her desire to travel someday, so Shelly concocts a plan for her to go to
Los Angeles during her spring break, where she can stay with her uncle Phil and do research on her mother, who lived in Los Angeles growing up. Initially resistant, believing she is too young to be traveling by herself and fearing what might happen to her there, Harry lets Vada take the five-day trip. Upon arrival, Vada encounters an adolescent boy named Nick who picks her up on Phil's behalf; he is the son of Phil's girlfriend Rose Zsigmond, who operates a car repair shop where Phil is now a mechanic. Vada notices that her uncle has trouble with commitment, while he and Rose live together. Although initially annoyed about sacrificing his own spring break, Nick assists her with the difficult task of obtaining more information about her mother by taking her around the city. Initially planning to visit her mother's high school, Vada discovers that it was destroyed in a fire. Nevertheless, she and Nick eventually track down a yearbook and meet several people who knew Maggie in high school, including police officer Daryl Tanaka, photographer Stanley Rosenfeld, and film director Peter Webb. Vada also meets her favorite poet, Alfred Beidermeyer, who also lives in Los Angeles, but is dismayed when he advises her not to become a writer. Later on, Nick and Vada sneak out to visit some Hollywood attractions, during which time she also gets her ears pierced, despite Nick's opposition. Shockingly, Vada also learns that her mother was once suspended from school for smoking and was previously briefly married to a man named Jeffrey Pommeroy. Emotionally crushed, she suspects that Jeffrey may actually be her biological father instead. Realizing he could unlock her mother's past, she successfully implores the police to locate him, and when she arrives at his residence, he instantly remembers Maggie. He provides Vada with valuable information for her essay, explaining the date written on the paper bag and showing her a home movie featuring Maggie singing the Charlie Chaplin composition "
Smile", which greatly touches her. Jeffrey also assuringly explains that he is not her father, explaining they divorced before Vada was born because Maggie wanted stability and a family, which her father Harry was able to provide. Meanwhile, Phil tries to prove his love to Rose after cardiologist Sam Helburn, a frequent patron of the repair shop who owns a fancy car, repeatedly stops by and continuously attempts to romance her. When Phil finally gets the courage to show how much she means to him, he proposes to her, and she accepts it happily. After she and Nick part ways at the airport, Vada boards the plane to return to Pennsylvania, discovering that he has gifted her a pair of earrings in her backpack as a memento. Upon arriving home, she is informed that Shelly has recently delivered the baby and meets her newborn half-brother at the hospital. To calm his crying, Vada cradles him in her arms and sings "Smile". She ultimately receives an A+ on her essay, vowing to eventually share her findings with him when he is older. ==Cast==