A field trip ignites Addie's desire to solve a centuries-old mystery: what happened to Lady Margaret Fraser? With the help of her older sisters Keedie and Nina, Addie begins her search for answers.

Addie's older sister Nina gives her a makeover. Later, when Addie gives a speech in front of the town council, she is heartbroken to find that her new best friend Audrey, who promised to support her, doesn't show up to hear her speech.

Addie and Audrey solidify their friendship when they go door to door to spread the word about the women who were wrongfully accused as witches. To heal the rift between her twin sisters, Addie plans a party for their upcoming birthday.

Despite Mr. MacIntosh's strict rules about using the town hall and Miss Murphy's attempts to shut it down, Addie’s birthday party for Nina and Keedie is a success. But when Addie's bully Emily crashes the party, things take a downward turn.

Keedie avoids her new friends out of fear they'll treat her differently if they know she has autism. Addie's fundraising campaign disrupts a beloved town event, which turns into the opportunity Miss Murphy needs to take control of the town council.

Addie's mum accidentally invites Jenna to Addie and Audrey's slumber party. Addie reads from Lady Margaret's diary about her attempt to rescue her servant, Beth. Jenna questions Keedie on the rift between her and Miss Murphy.

Backstage drama threatens the school's production of Macbeth. Emily's jealousy reaches a breaking point and she lashes out at Addie. Nina and Keedie must then rescue their little sister from the wrath of Miss Murphy.

Both at low points following their confrontations with Miss Murphy, Addie, and Keedie turn to each other for healing. Frank creates a much-needed diversion for Nina when he recruits her to help him find a lost turtle.

Addie's fate at her school is decided. Audrey and Frank discover the amazing story of Lady Margaret's escape, inspiring Addie to make one final plea to the town for a memorial for young women wrongfully accused as witches.