The young, beautiful, calm‑and‑forthright Claire Bennett steps into Hawthorne Estate for the very first time, only to be greeted by three notoriously unruly children wielding red paint, broken glass and mechanical booby‑traps. They have driven away eight stepmothers already — and Claire is the ninth. She soon realises what the children truly want to figure out is not how capable she is, but this: when will she leave too.
Adrian Hawthorne, the head of the Hawthorne household, signs a one‑year contractual marriage worth one‑and‑a‑half‑million‑US‑dollars with Claire, tasking her with the household and the three children’s education. Claire neither curries favour nor spoils them. She makes Leo, who loves setting traps, learn to face the consequences of his actions. She compels Lily, who buys friendships with money, to recognise genuine versus fake relationships. She also demands Ethan, who regards himself as the heir‑to‑be, prove himself through real competence. Little by little, the three children come to understand: though Claire disciplines them, she will never abandon them. Leo is the first to call her “Mom”. Lily grows reliant on her, and Ethan, who resisted her most fiercely, slowly accepts her as well.
Just as Claire truly begins to fit into the family, Fiona Grant, the children’s biological mother, returns. Fiona still loves her kids and tries to win her way back to Adrian by leaning on her status as their birth mother and the business resources of the Grant family.