Based on the classic novel by Susan M. Coolidge and told in the tradition of Anne of Green Gables, What Katy Did is a warm family drama that tells the story of Katy Carr (Alison Pill), a headstrong 13-year-old growing up in the countryside at the turn of the century.
Katy's feisty streak and mischievous antics try the patience of her widowed dad, Dr. Philip Carr (Kevin Whately), and her stern Aunt Izzie (Martha Burns), who share the responsibility of raising Katy and her siblings.
Katy's outlook begins to change, however, with the arrival of her ill cousin Helen (Megan Follows), who exposes Katy to a world she never knew existed.
Then, when a tragic accident confines Katy to her room, she gains strength from Helen's wisdom and a renewed zest for life.