Gymnast Elizabeth looks nothing like her mother and never knew her father. When registration requires her birth certificate, she's drawn into a spiral of anxiety and betrayal as she tries to find out if she's actually her mother's daughter or someone else entirely. Complicating things is her longing for ex-friend and neighbor Zach, whom she warned off years ago but now thinks of often. After a fight with her mother gets Liz disqualified from a meet, Zach finds her walking home and insists on taking care of her. He reveals that he found a watch in an old playhouse they used as children and that he believes it's a time machine. Powered by her vaulting (to offset the need for great speed when time-traveling), Liz travels to seemingly random times and places, where she might discover the truth of her parentage, which she becomes sure involves a semi-famous gymnast she's been studying. The turn from realism into sf is a little jarring, but this is nonetheless recommended for larger collections.

A time-travel novel with a gymnastics twist, adult author McCabe's debut YA novel follows high school athlete Elizabeth Arlington in her quest to find answers about her biological parentage.After living with unresolved questions that her older, widowed mom is cagey about, a secret DNA test reveals to Elizabeth that her ancestry is 70% European and 30% Han Chinese, surprising her, since neither of her blond parents appear to have Asian heritage. Zach, Elizabeth's best friend, convinces her to try using a mysterious old watch they'd stumbled across that he believes is a time machine. Elizabeth ends up cycling through dates programmed into the watch, which are notable in part for their importance to international gymnastics or to Elizabeth's biological mother, an Olympic hopeful. McCabe portrays each interconnected generation of women as appealingly resourceful, if understandably distressed by their circumstances, and their grit propels much of the story. Once Elizabeth has mostly unraveled her initial mystery, a new obstacle appears, and Elizabeth must race through time to prevent a family disaster. The antagonist's motivations, however, feel murky and her personality, mutable according to narrative necessity. The author raises questions about adoption and its potential for trauma but does not examine its impact on Elizabeth. Elizabeth's small-town Pennsylvania community is largely white; her feelings about her newly discovered biracial background are also not addressed.Despite the original premise, a book let down by limited exploration of the subjects raised. (Science fiction. 12-17)