Parisian private investigator Aimée Leduc doesn’t know that her life is about to be upended. Her ex, Melac, has been hounding her to move their daughter, Chloé, to Brittany. Aimée has stopped answering his calls, which is why she doesn’t know he’s waiting for her by the Bassin de la Villette as she leaves a client’s office late one night. When she finds him, he has just been stabbed by an assailant, who knocks Aimée unconscious and plants the bloody knife in her hands. Now Aimée is in police custody, debilitated by a concussion, with overwhelming evidence pointing to her as Melac’s killer. In an attempt to figure out who the real culprit is, she goes deep into the underbelly of Paris’s 19th arrondissement, where she rubs shoulders with biker gangs, paranoid journalists, grieving parents and frustratingly tight-lipped ex-cops on her hunt for justice.

October 1942: It’s been two years since Kate Rees was sent to Paris on a British Secret Service mission to assassinate Hitler. Since then, she has left spycraft behind to take a training job as a sharpshooting instructor in the Scottish Highlands. But her quiet life is violently disrupted when Colonel Stepney, her former handler, drags her back into the fray for a risky three-pronged mission in Paris. Each task is more dangerous than the next: Deliver a package of forbidden biological material. Assassinate a high-ranking German operative whose knowledge of invasion plans could turn the tide of the war against the Allies. Rescue a British agent who once saved Kate’s life --- and get out.

In the wake of 9/11, Paris is living in a state of fear. For Aimée Leduc, November is bittersweet: the anniversary of her father’s death and her daughter’s third birthday fall on the same day. A gathering for family and friends is disrupted when a bomb goes off at the police laboratory --- and Boris Viard, the partner of Aimée’s friend Michou, is found unconscious at the scene of the crime with traces of explosives under his fingernails. Aimée doesn’t believe Boris set the bomb. When a member of the French secret service drafts Aimée to help investigate possible links to an Iranian Revolutionary guard and fugitive radicals who bombed Interpol in the 1980s, Aimée uncovers ties to a cold case of her father’s.

Kate Rees, a young American markswoman, has been recruited by British intelligence to drop into Paris with a dangerous assignment: assassinate the Führer. Wrecked by grief after a Luftwaffe bombing killed her husband and infant daughter, she is armed with a rifle, a vendetta and a fierce resolve. But other than rushed and rudimentary instruction, she has no formal spy training. Thrust into the red-hot center of the war, a country girl from rural Oregon finds herself holding the fate of the world in her hands. When she misses her mark and the plan unravels, Kate is on the run for her life --- all the time wrestling with the suspicion that the whole operation was a setup.

Parisian private investigator Aimée Leduc gets an emergency phone call from her daughter’s playgroup: Aimée’s own mother, who was supposed to pick Chloe up, never showed. As Aimée and Chloe leave the playground, Aimée witnesses the body of a homeless woman being wheeled away from the neighboring convent, where nuns run a soup kitchen. The last person anyone saw the dead woman talking to was Aimée’s mother, who has vanished. Trying to figure out what happened to Sydney Leduc, Aimée tracks down the dead woman’s possessions, which include a huge amount of cash. What did Sydney stumble into? Is she in trouble?

A dying man enters the office of Éric Besson, a lawyer in Paris’s 13th arrondissement. He is carrying a dilapidated notebook full of meticulous investment records. For decades, he has been helping a cadre of dirty cops launder stolen money. The notebook contains his full confession. He is adamant that Besson get the notebook into the hands of La Proc, Paris’s chief prosecuting attorney, so the corruption can finally be brought to light. But en route to La Proc, Besson’s courier --- his assistant and nephew --- is murdered, and the notebook disappears. Private investigator Aimée Leduc is reluctant to get involved, as her father was a cop and was murdered by the same dirty syndicate the notebook implicates.

Private investigator Aimée Leduc is walking through Saint-Germain when she is accosted by Suzanne Lesage, a Brigade Criminelle agent on an elite counterterrorism squad. Suzanne has just returned from the former Yugoslavia, where she was hunting down dangerous war criminals for the Hague. Back in Paris, Suzanne is convinced she’s being stalked by a ghost --- a Serbian warlord her team took down. She’s suffering from PTSD and her boss thinks she’s imagining things. She begs Aimée to investigate; is it possible Mirko Vladić could be alive and in Paris with a blood vendetta?

November 1989: Aimée Leduc is in her first year of college at Paris’s preeminent medical school. She lives in a 17th-century apartment that overlooks the Seine with her father, who runs the family detective agency. But the week the Berlin Wall crumbles, so does Aimée’s life as she knows it. First, someone has sabotaged her lab work, putting her at risk of failing out of the program. Her father takes off to Berlin on a mysterious errand and asks Aimée to help out at the detective agency while he’s gone. But the case Aimée finds herself investigating --- a murder linked to a transport truck of Nazi gold that disappeared in the French countryside during the height of World War II --- has gotten under her skin.

Aimée Leduc has her work cut out for her --- running her detective agency and fighting off sleep deprivation as she tries to be a good single mother to her new bébé. The last thing she has time for now is to take on a personal investigation for a poor manouche (Gypsy) boy. But he insists his dying mother has an important secret she needs to tell Aimée concerning Aimée’s father’s unsolved murder a decade ago. How can she say no? The dying woman’s secret is even more dangerous than her son realized.

A serial rapist has been terrorizing Paris's Pigalle neighborhood, following teenage girls home and attacking them in their own houses. It is sad and frightening but has nothing to do with Private Investigator Aimée Leduc --- until Zazie, the 13-year-old daughter of the proprietor of Aimée's favorite café, disappears. The police aren't mobilizing quickly enough, and when Zazie's desperate parents approach Aimée for help, she knows she can’t say no even if she wanted to.

Yuri Volodya, a mysterious old Russian man, hires Aimée Leduc to protect a painting. By the time she gets to his Montparnasse atelier, the precious painting has already been stolen. The next day, Yuri is found tortured to death. Some very dangerous people are threatening Aimée and her co-workers, and witnesses are dropping like flies. Now Aimée has to find the painting, stop her attackers, and figure out what her long-missing mother has to do with all this.

A missing young woman, an illegal immigrant raid in progress, botched affairs of the heart, dirty policemen, the French secret service, cutting-edge science secrets and a murderer on the loose --- what has Aimée Leduc gotten herself into? And can she get herself --- and her friends --- back out of it all alive?