In the beginning, she lives with her father, Barney, who is a gambler and moves around constantly to escape his gambling debts. (her mother died when she was little.) When he finally hits it big, however, he is beaten up and the money stolen. While he is recuperating in the hospital, Casey gets sent to live with Uncle Phil, her mother's brother, who is a big-shot lawyer.
However, Casey doesn't settle well there, so she gets sent to stay with her Paw-Paw, or maternal grandmother, in San Francisco's Chinatown. Paw-Paw is fairly easy-going, and works at a sweatshop sewing clothes, since her Social Security check doesn't cover all her expenses. While living there, Casey learns about Chinese culture, including a family legend that they are descended from an owl maiden that turned human by removing her feather dress and married a mortal man, and is told about her mother.
It takes awhile for Casey to adjust to living in Chinatown, since, like the author, she is 'too American for Chinatown, but too Chinese everywhere else'. However, she does eventually befriend a classmate at the Catholic school she attends (she was sent there because the school has a Chinese class), and settles in. She doesn't have much contact with her father, however, since when he was released from the hospital, he started gambling again (thinking that his luck had changed for the better), ending up losing a thousand dollars and having to move even more in order to escape the debts.
Meanwhile, an envelope with five dollars starts appearing in Paw-Paw's mailbox once a week. Casey assumes that Barney called in a favor from a friend, and uses the money to buy extra food for her and Paw-Paw to enjoy.
Towards the end of the book, someone breaks into the apartment to steal the jade owl charm necklace that Paw-Paw owns, and she breaks her ankle when confronting the thief. While she is in the hospital, Casey and her friend investigate, and discover that Barney was the one that broke in, hoping to sell the charm in order to cover his gambling debts. When Barney reveals that he hasn't been sending the money, Casey then figures out that the sender is actually Gilbert, the grandson of Paw-Paw's friend Mr. Jeh. She confronts the guy about it and gets him to stop, but he insists on taking her and Paw-Paw out to dinner once a week.
The book ends with Barney joining Gamblers Anonymous in order to break his gambling addiction and Paw-Paw selling the charm to a museum to help her son-in-law.
Child of the Owl contains examples of:
- Cool Old Guy: Paw-Paw's friend, Mr. Jeh, who is very nice to Casey, has the energy of someone younger, and was able to knock out a person which a thick book that was checked out of library specifically to use as a weapon.
- Disappeared Dad: Since Barney is first in the hospital, then running away from his gambling debts, he can no longer take care of Casey, which is why she is living with Paw-Paw.
- Embarrassing First Name: Casey's friend doesn't like her first name, Tallulah, or her nickname, preferring the name Talia. Casey's not a fan of her name, either, as she was named after the baseball player Casey Stengel (he was manager of the Yankees when Barney won a lot of bets that helped pay the hospital bills when she was born) and prefers her Chinese name of Chuen Mei (means Taste of Spring).
- Fish out of Water: This happens to Casey when she first moves to Chinatown.
- Friendly Local Chinatown: Casey lives in San Francisco's Chinatown for most of the book.
- The Gambling Addict: Casey's father, Barney.
- Granny Classic: Paw-Paw, with some shades of Cool Old Lady
- Language Barrier: Casey was never taught Chinese, so she has some difficulty fitting in when first living in Chinatown. After a few months of Chinese class and help from her grandmother and best friend, she eventually picks up some of the language and starts becoming fluent.
- Missing Mom: Casey's mother, Jeanie, died when Casey was little.
- Named After Someone Famous: Casey's friend was named Tallulah after actress Tallulah Bankhead.
- Only Known by Their Nickname: Casey's friend was named Tallulah, after Tallulah Bankhead, her great-aunt's favorite actress, but after an incident in elementary school where she used a bobby pin to pick her nose, is thereafter called Booger by her classmates. Towards the end of the book, she says she wishes her name was Talia, and Casey thereafter calls her that. Also, Casey's cousin Pamela is called Pam-Pam.
- Parental Abandonment: Casey's mother died when she little, and her father can't take care of her due to his gambling debts.
- Raised by Grandparents: Casey is raised by Paw-Paw after her father can no longer take care of her and her Uncle Phil doesn't want her, thinking she'd be a bad influence on his daughters Annette and Pam-Pam.
- Shapeshifting: The story behind the owl charm involves owls that can turn into humans by removing their feather dresses. Casey's supposed ancestor is an owl that took human form and married a human male in order to protect her family.
- Tomboy: Casey is something of a tomboy, not caring for dresses, and outside of her school uniform, normally just wears jeans and a sweatshirt. Besides the school uniform, she only owns one dress, which is a hand-me-down from her cousin Pam-Pam.
- Tropaholics Anonymous: Barney joins Gamblers Anonymous in order to break his gambling addiction at the end of the book.