Disguised with a fake mustache, Nora is the first woman to attend the Royal Academy of the Arts in London in 1894. Her ruse is upended when the Academy admits its first official female student, insufferable heiress Margueritte Durand.

A college student named Max recounts his childhood memories from the late 1990s, in which he becomes best friends with a boy named Arthur. As Max and Arthur gather both true and fictitious information about Arthur's neighborhood, they begin to dream up fantastical stories and fictional biographies about the eccentric people who live on Arthur's street, a mysterious place called Locust Lane.