Piranesi Summary

Piranesi lives in a labyrinth called the House. It is comprised of an infinite number of halls, each lined with statues. The house has three levels: the Drowned Halls, which are filled with water; the Upper Hals, which are filled with clouds; and the Middle Halls, where Piranesi lives. Every day, Piranesi records his experiences in his journals, including his observations of the tides and any discoveries he makes. As far as he knows, he has always lived in the House, and besides the 15 skeletons, there is only one other human: the Other.

Piranesi meets several times a week with the Other to discuss their shared project: uncovering the “Great and Secret Knowledge” which is supposedly hidden in the House. The Other believes this knowledge will grant him special powers. Though Piranesi cares little for these abilities, he still assists the Other, taking notes for him and traveling to places the Other is afraid to go himself. After all, the Other is Piranesi’s best friend.

Upon returning from a particularly difficult reconnaissance mission for the Other, Piranesi finally expresses his doubts about their project. To his surprise, the Other tells him they have already had this conversation, explaining that the House has given Piranesi amnesia. Piranesi is skeptical but decides to read through his journal for any discrepancies. In the meantime, he decides to continue helping with the Other’s project, if only for companionship.

The Other reveals he has met a 16th person—16—and warns Piranesi to avoid them: they are an enemy, and their words will drive Piranesi insane. Piranesi promises to avoid stranger but breaks his promise. He meets an elderly man whom he nicknames the Prophet for his seemingly God-like knowledge of the House. According to the Prophet, the House is a distributary world, a receptacle for old ideas flowing out another one. He further reveals that the Other was his former student and that the Other’s search for the “Great and Secret Knowledge” is in vain. Out of spite, the Prophet promises to lead 16 to Ketterley—his name for the Other.

Reading through his journals, Piranesi discovery many entries he does not remember writing. In these entries, he reads about a man named Laurence Arne-Sayles, who claimed to have discovered lost worlds. Piranesi reads about Arne-Sayles’s various disciples, many of whom disappeared under mysterious circumstances. One of them, James Ritter, was found imprisoned in Arne-Sayles’s home in 1997. Questioned by the police, Ritter claimed to have spent several years in an endless labyrinth of halls and statues.

Piranesi realizes he does in fact have amnesia and recovers several scraps of paper from a gull nest. Reconstructing them, he reads a first-person note from a man losing his memory. Piranesi discovers a note in chalk left by 16, but he erases it in observance of the Other’s warnings. The next day, however, he returns and reads what is left of the note. Piranesi searches for the words from the note in the index of his journals. He reads more about Laurence Arne-Sayles and reflects on his similarities with the Prophet.

Sixteen leaves another note for Piranesi, this time in pebbles. It asks: “ARE YOU MATTHEW ROSE SORENSEN?” The question provokes a visceral response from Piranesi, sparking confusing memories. He looks up Sorensen in his journals and discovers several entries detailing plans to write a book on Arne-Sayles. He then searches for entries related to Ketterley but is shocked to discover the pages about Ketterley have been ripped out. However, Piranesi realizes the paper he recovered from the gull nest are the missing pages from his journals.

Written by Matthew Rose Sorensen, the entry on the missing pages describes Matthew’s visit to Valentine Ketterley’s house. He is there to learn about Arne-Sayles. The conversation goes badly, but suddenly Ketterley offers to show Matthew how to access one of the lost worlds. Matthew obliges him, amused by the strange ritual Ketterley performs. When he opens his eyes, however, Matthew realizes he has been transported to a new world. Ketterley laughs evilly.

Piranesi realizes he was wrong about the Other: he is his enemy, not his friend. Recognizing 16 as his ally, Piranesi worries she will be caught in a coming flood. He writes a note for her, but Ketterley erases it. On the day of the Flood, Piranesi trails Ketterley, reasoning that 16 must be trailing him. Piranesi confronts Ketterley, eventually revealing he has learned the truth. Ketterley reaches for his gun, but Piranesi kicks it away. Just then, 16 emerges, and together, 16 and Piranesi begin climbing to escape the coming floods.

Piranesi warns Ketterley to get into his boat, but Ketterley shoots at Piranesi and 16 instead. A massive tide sweeps into the Hall, and Ketterley drowns. After the tides recede, 16, whose name is Raphael, introduces herself as a British detective investigating the disappearances surrounding Arne-Sayles. She asks Piranesi to return home to his family, who have missed him for six years. Piranesi is initially unsure, but he eventually decides to accompany her back to the real world.

The narrator—no longer solely Piranesi or Matthew—describes his troubles adjusting to the real world. Concepts like money and possessions do not make much sense to him, and he does not relate much to the life of his former self, Matthew. He often returns to the House to escape, sometimes accompanied by Raphael or James Ritter. Sometimes, he simply imagines being back in the House. In the final scene, the narrator takes a walk through a park. Looking at the world around him, he reflects on the “beauty” of the House and its “infinite kindness.”