Stargirl, living now in Pennsylvania, tells her own story this time, in "the world's longest letter," which is actually a series of journal entries. New in town, homeschooled, and feeling rejected by Leo, the 16-year-old narrator of the first book who had fallen under her spell, she is lonely and sad -- her "happy wagon," where she keeps stones representing her level of happiness, is almost empty.
But this eccentric extrovert begins to meet new people, and Stargirl's life soon includes a little girl, a middle-aged agoraphobic, the donut lady, a crabby tween, an elderly man who spends all his time at his wife's grave, and a possible delinquent. But she's still pining for Leo.