Lea walks her usual route through the city when a young man steals her bag. She chases him into an alley but quickly loses her bearings - each alley leads into yet another alley, the sounds of the city fades away, and the thief is nowhere to be seen. Hopelessly searching for an exit, she eventually encounters Dee, one of the "alleyfolk" who obsessively makes maps of his surroundings and is convinced that the alleys have been gradually narrowing over time. The more of these alleyfolk Lea gets to know, the more she sees that they agree: the labyrinth they inhabit is shifting, creating a state of deep uncertainty. When the presence of the thief becomes a subject of contention, Lea finds herself entangled in the affairs of a world fated to end soon. Closing Act explores the complex networks that make up a city. The discovery of this strange, shifting environment leaves its inhabitants to face a looming existential threat.