Lina Mayfleet is one of the returning protagonists from The City of Ember. She is about 12 years old and worked as a running messenger in Ember. In this novel, she lives with Poppy, her infant sister; Mrs. Murdo, their guardian; Torren Crane, Dr. Hester’s young nephew; and Hester Crane, Sparks’ only doctor. Lina feels stifled by her life in Sparks until she is able to exercise some agency. She also struggles with Torren’s animosity.

Because of her penchant for exploration, Dr. Hester’s chores bore her. She feels that her job in Ember was both more important and more interesting; she laments that “[w]hile everyone else was out in the village, doing new, interesting things and meeting new people, [she] was stuck doing housework” (119). She feels disconnected from both the people of Sparks and the rest of the Emberites. When visiting Doon for the first time, she “felt a sudden longing to have her own room there, back among her old friends and neighbors” (101). This feeling of restlessness abates once she stows away with Caspar and Maddy. It is only once she makes the choice to leave Sparks that she truly feels like it is her home. The night before entering the city, Lina is struck by homesickness, but “for the first time, the picture that arose in her mind [of home] was not of the dark, familiar buildings of Ember but of Sparks under its bright sky” (228).