Batman: Nightwalker is part of the DC Icons series, a collection of standalone young adult novels reimagining iconic DC superheroes. The novel presents an origin story for Bruce Wayne set in a version of Gotham City where he is eighteen, newly wealthy, and not yet Batman.
The story opens with an unnamed young woman cleaning up after a murder at the mansion of a wealthy philanthropist, Sir Robert Grant. She spray-paints a symbol on the wall and attempts to flee, but police arrest her. She surrenders calmly, smiling as if the capture is only temporary.
On his eighteenth birthday, Bruce Wayne drives to a charity benefit in a custom Aston Martin built by WayneTech, his family's technology company, bantering with Alfred Pennyworth, his guardian. He reflects on his murdered parents and on the contrast between Gotham City's gleaming skyscrapers and its impoverished neighborhoods. At the benefit, he reunites with his best friends, Dianne Garcia and Harvey Dent, but leaves early after Richard Price, the mayor's son, asks Bruce to fake a WayneTech internship and grows hostile when Bruce refuses.
Driving aimlessly, Bruce encounters a police blockade where officers confront a suspect linked to the Nightwalkers, a shadowy criminal network targeting the wealthy. A getaway car races through the barricade after an explosion, and Bruce chases it, rams it, and flips it. Two weeks later, he is convicted of obstruction of justice and sentenced to community service at Arkham Asylum, Gotham City's notorious prison for the criminally insane, under the supervision of Detective Draccon of the Gotham City Police Department (GCPD).
Under Dr. Zoe James, Arkham's head warden, Bruce mops floors and endures inmates' taunts. In the intensive-treatment basement, he discovers a prisoner who has not spoken in months: a girl his own age who sits folding a napkin into a flower that transforms into a scorpion. She eventually speaks to him, identifying him as Bruce Wayne and advising him not to hold back. She introduces herself as Madeleine. Meanwhile, Harvey stays at Wayne Manor, Bruce's family estate, to escape his physically abusive father but refuses Bruce's urging to report the abuse.
Because Madeleine has spoken only to Bruce, Draccon recruits him to interrogate her. She shows him Madeleine Wallace's file: eighteen years old, the youngest inmate in Arkham's history, accused of three murders of wealthy philanthropists killed in their homes with their security systems reprogrammed and bank accounts drained. Each victim's legacy was then destroyed through Nightwalker bombings. Lucius Fox, Bruce's mentor at WayneTech, has installed new security on Bruce's accounts because he matches the Nightwalkers' target profile. Draccon equips Bruce with a hidden microphone, but Madeleine instantly detects the surveillance. Bruce throws the devices away, gambling that honesty will earn her trust.
In subsequent visits, Madeleine shares pieces of her past and directs Bruce to investigate the north wall of the Bellingham Industries building. Following her clue, Bruce finds a hidden passage leading to an underground weapons cache and escapes after fighting a Nightwalker supply runner. Police discover the hideout without knowing Bruce was involved. On a later visit, Madeleine shows Bruce bruises on her arms, claims they came from a struggle with staff, and shares that her mother was imprisoned for killing a negligent doctor. She hints that Bruce could visit without surveillance using a frequency scrambler.
A thunderstorm knocks out Arkham's power and opens cell doors. Bruce fights escaped inmates to protect Madeleine's cell; she notably does not try to escape. Draccon removes Bruce from the basement. Researching independently, he discovers Madeleine's mother, Eliza Eto, committed a premeditated stabbing, not the impulsive act Madeleine described. Bruce suspects Madeleine's repeated origami gestures in interrogation footage are coded signals to accomplices outside Arkham. At WayneTech, Lucius shows Bruce bulletproof chain-mail armor and the Ada drones, large AI-driven security robots set to debut at a Wayne Foundation charity gala. Bruce secretly pockets a frequency-scrambling device.
Mayor Price is murdered by the Nightwalkers. Bruce uses the device to visit Madeleine off the record at Arkham. She warns he is on their target list because of his wealth and WayneTech's police contracts. Draccon discovers Bruce and removes him from the case. When Bruce mentions Madeleine's bruises, Draccon reveals that Madeleine receives no IV medication and is never removed from her cell, meaning she lied.
Draccon drives Bruce home to find Wayne Manor's security disabled. The Nightwalkers have sealed Bruce inside, replicating their method with previous victims. Bruce fights attackers dragging a bound, bleeding Alfred and frees him. A third figure in metal-jointed armor fires at Bruce before escaping. Bruce overhears that Madeleine provided the intelligence for the invasion. At the hospital, Draccon reveals Madeleine has escaped Arkham by exploiting the camera malfunction Bruce caused. She left a folded note thanking Bruce that folds into both a flower and a diamond. Draccon arrests Bruce as a suspect.
From a holding cell, Bruce watches the Nightwalkers seize the Gotham City Concert Hall during the gala, taking over a hundred hostages including Lucius and Dianne. Madeleine has hacked the Ada drones and turned them against police. Bruce recognizes the diamond shape of her note as a clue matching the gala's logo. Harvey frees Bruce from jail with Alfred's help. Alfred reveals Bruce's older bank accounts have been drained, though Lucius's newer security held. Bruce breaks into WayneTech, takes the armor, activates an uninfected drone, and enters the concert hall through an underground tunnel.
Inside, Bruce fights through guards and reaches the mezzanine. Madeleine, in military gear, recognizes him by his gait. Richard is revealed as a Nightwalker recruit, terrified and regretful, holding Dianne hostage. Madeleine forces Bruce to surrender, and he is knocked unconscious. He wakes as her captive. She reveals her brother, Cameron Wallace, is the true leader of the Nightwalkers. Cameron's death was faked after an experimental procedure saved his life and gave him the metal-jointed armor Bruce encountered at Wayne Manor. Madeleine confirms she took the fall for Cameron's murders, hacking victims' security while Cameron killed them, and went to Arkham voluntarily to shield him.
Alone with Bruce, Madeleine kisses him. Cameron then orders her to extract access to Bruce's remaining accounts. She agrees to release hostages, including Dianne and Lucius, in exchange for Bruce's cooperation. Bruce types in his code, knowing Lucius's security system will flag the unauthorized access and remotely disable the computers controlling the hacked drones. The drones reset, and police break through. Cameron tries to shoot Bruce, but Madeleine deflects his aim.
On the rooftop, Cameron seizes Madeleine's gun and fires at Bruce but hits Madeleine. Enraged, Bruce attacks Cameron and knocks him unconscious. Police arrive by helicopter. Cameron surrenders but directs their fire toward Madeleine. Bruce drags her behind cover, and police shoot Cameron dead. Bruce holds Madeleine as she appears to die, telling him he fights for the wrong side. He kisses her, dons his helmet, rappels off the roof, and vanishes.
In the aftermath, Alfred's cover story is accepted. Harvey moves into Wayne Manor after finally reporting his father. Detective Draccon visits with her replacement, Detective James Gordon, to clear Bruce's record and present a certificate of honor. She reveals Madeleine's body vanished from the hospital; she had already fled the country. Her death was another deception. Gordon adds that Madeleine funneled the Nightwalkers' stolen money into the Gotham City Legal Protection Fund, the charity Bruce's mother always supported. One month later, Bruce stands on the concert hall rooftop, rereading Madeleine's note. He resolves to remain in Gotham City and protect the place he now sees as home.