Tamsin was predicted to be one of the most powerful witches in her family when she was born; however, her Talent is a no show on her eighth birthday. To escape the shame she feels, Tamsin who is now seventeen convinces her parents to allow her to attend boarding school. Tamsin is thrilled that the school requires all students to live in the dorms since it means her parents can’t force her to live with family. Although she tries to live a normal life as someone who is Talentless, Tamsin does work in her grandma’s store which is where she encounters a professor who is part of a rival witch family. Alistair, of course, doesn’t reveal that to Tamsin so she agrees to help him. Only after it is too late to turn back does Tamsin discover the truth about Alistair and the clock he asked her to find.
The plot of Once a Witch moves along nicely and has a great twist that comes as an excellent shock to Tamsin. There’s an appropriate amount of tentative high school romance to go along with the suspense of discovering the secret surrounding the clock and how it ties to Tamsin’s family. It’s a quick read ending with a cliffhanger that implies there will be a sequel if not an entire series.