The following version of this book was used to create this study guide: Modiano, Patrick. Invisible Ink. Yale University Press, 2020. Print. Translated from the French by Mark Polizzotti.

The novel is narrated in the present-tense by Jean Eyben, a 65-year-old man who is writing a novel about his obsession with a case he worked almost 50 years ago during his brief time as a detective. While speaking about the past, he switches to the past-tense, so that the novel is constantly transitioning from the narrative present to the past.

Back when he was barely 20, he had decided to take a job at Hutte Detective Agency so that it might inspire him as a writer at a later date. His first assignment had come from Hutte himself, who gave Jean a case file on a woman named Noëlle Lefebvre. A man named Brainos had come into the office and had given Hutte a few details about Noëlle, whom he claimed was a friend of his who had disappeared and who might have been living with a fake identity in the first place. Hutte had written down a few details of the case on three pages of paper. Brainos had also given Hutte Noëlle’s general delivery card for the post office, and the card had a blurry picture of Noëlle on it.

Hutte gave Jean the case file and the general delivery card and tasked him with investigating. First, Jean went to the apartment on Rue de la Convention where she had lived. The concierge said she had not seen Noëlle for over a month. At the post office, Jean attempted to pick up Noëlle’s mail, but there was nothing for her. Next, Jean went to a café Noëlle supposedly frequented often. The bartender said he had not seen Noëlle.

A man named Gérard Mourade came in and asked Jean why he was looking for Noëlle in a hostile manner. Jean pretended he was a friend of hers who had met her in the office of a man named Brainos. He said they had bonded over being from Annecy. Although Gérard was suspicious, he believed Jean and revealed to him that Noëlle worked at Lancel, a luxury leather goods shop. She had been married to a man named Roger Behaviour and they had lived together on Rue Vaugelas. Jean accompanied Gérard to their apartment. When he was alone, he found a secret compartment inside a bedside drawer. Inside, he found a datebook belonging to Noëlle. He stole it and took it home with him.

Jean inspected the datebook and found about 20 scattered entries that gave him almost nothing to go on. He tried to track down a few names and places, but came up empty. One day, a letter arrived at the post office for Noëlle from a man named Georges. Georges urged Noëlle to return to Rome with a man named Sancho. He told her to get in touch with him through a man named Mr. Mollichi, who worked at the La Marine Dance Club. Jean took this information to Hutte, and Hutte revealed that Georges was Georges Brainos, the man who had hired them. Hutte said that he did not much care about the case.

Ten years after he met Gérard, Jean saw his picture in a yearbook while getting his hair cut. The yearbook had the name of an agency. When Jean called, they informed him that they had two addresses on file for Gérard.

Either right before or right after this event, Jean had tracked down Mr. Mollichi, who had informed him that Brainos had died. Mr. Mollichi promised to be in touch if he heard from Noëlle.

In the narrative present, Jean says that he has tried using the internet to find Noëlle to no avail. He says he should stick to chronological order since he has forgotten crucial events that took place between the moments he has already written about.

Jean decides he cannot stick to chronology without impeding his writing flow. He remembers that during the same year he found the yearbook, he ran into a friend from Annecy, Jacques, who was now a reporter. Jean asked Jacques if he knew anyone named Noëlle Lefebvre. Jacques said he knew someone named Sancho Lefebvre, an older man who had driven an American car. He had left Annecy with a young woman. Jean thought back and remembered he had once accepted a ride home from a boy named Daniel who had stolen an American car from a man named Serge Servoz. Years later, he had seen Daniel on a bus.

In the narrative present, Jean looks through Noëlle’s datebook and sees that a new entry has appeared, written in a paler blue ink. Fifteen years ago, Jean happened by a garage that was owned by Roger Béavioure, whom he realized was Roger Behaviour. He went inside and asked Roger about Noëlle. Roger faintly recalled her and Gérard. He said Gérard was unhinged and often made up lies, including one in which he had murdered a man.

Once, Jean had run into a man who looked like Gérard at a pharmacy, but he had claimed to be Andre Vernet. Jacques had sent a letter shortly after their meeting which had included an article about an actor named Andre Vernet who used the stage-name Gérard Mourade. Andre/Gérard had been kidnapped by a man whom he later killed. Jacques also said he had discovered Sancho’s real name was Serge Servoz-Lefebvre. Jean reread the letter and then put it in the file.

A narrative switch occurs and a third-person narrator begins to tell the story of Noëlle, an elderly woman living in Rome who has forgotten most of her past. A Frenchman comes into the gallery where she works and asks about her life in Rome. She slowly remembers details he mentions, including moving to Rome with Sancho. They have dinner and part, planning to meet up the next day. On her way home, she remembers that she had once ridden the bus with the Frenchman when they were just children. She plans to tell him the next day.