Ann Hopkins lives near the Turner siblings and finds herself entangled with the magical sand creature, the Psammead, alongside them. She is an original addition to the narrative.

Her interactions with the eldest Turner sibling, Sil, form a recurring dynamic. Sil harbors romantic feelings for her, leading to simmering jealousy when her attention turns elsewhere. This jealousy drives Sil to wish himself into Ann's form to disrupt her plans with another boy. Ann remains unaware of Sil's feelings throughout this incident.

Ann recognizes the Psammead's particular fondness for her and strategically employs a deliberately sweet and charming demeanor to influence the creature's cooperation, often securing her desired wishes.

Her experiences with the Psammead's magic carry risks. A misunderstanding once led the creature to transform her into a crystal statue, requiring the Turners to hide her petrified form until the magic faded at sunset. In another instance, she ventured alone with the Psammead into an explored mirror world, an adventure distinct from the group's usual activities.

A local affluent boy, Michael, also shows romantic interest in Ann, creating a triangular dynamic between her, Michael, and Sil. The two boys frequently vie for her attention, though Ann appears largely oblivious to their rivalry. This dynamic fuels several interpersonal conflicts among the children.