Isabel was an inactive Lucian until she met Vikram Kabra. She rose quickly among the ranks, proving that she was very ruthless. She could make the most secretive agents spill their secrets. When she married Vikram, she helped him with their art business. Her full name is Isabel Vesper-Hollingsworth Kabra.
She was visiting with Amy and Dan's parents the night of the fire, and was later proved to be the one that set the fire, and lit the match. After the Clue hunt Alistair Oh later gives evidence to the police against Isabel, for the murder of Arthur Trent and Hope Cahill, and it results in Isabel being sentenced to prison for life. Amy remembers Isabel holding her in her arms. Amy blames herself when she realizes that she gave away the location of Hope and Arthur's vacation (otherwise known as a Clue-hunting expedition), by correcting Isabel of what was on her night gown (Koalas, not teddy bears—that means they went to Australia). Isabel also doesn't like Amy and Dan Cahill, and suspects her son's crush on Amy, which she uses to her advantage. When Isabel tried to kill Amy, Dan, and Alistair Oh, by setting the building they were staying in on fire, Irina Spasky, a Russian ex-KGB agent, came to their rescue. In the process, Irina died. Since Isabel had started the fire and had decided not to save Irina, although she knew she could, Isabel is responsible for Irina's death.
Isabel is described by Amy as "a Lucian killing machine with pearls and perfume."
After the incident on Cahill Island, Isabel was put on trial. Ian and Natalie Kabra were present. Vikram went to Brazil to avoid questioning. Isabel was found guilty for first degree murder, as shown in The Black Book of Buried Secrets.
In the The Medusa Plot, Isabel was released from parole, only after paying huge sums of money and starting an organization called AidWorksWonders. She is called by Ian when Natalie is kidnapped, but says that she has no children, because her children had betrayed her.
It is revealed in The Dead of Night that the workers and children of AidWorksWonders, Isabel's organization, are actually actors paid by Isabel. Ian also found out that the Lucian paper he picked on DeOssie factory was a personalized sheet made by his mother, Isabel.
Isabel is revealed to be Vesper Two, The Vesper Shield in Trust No One. She appears to hate being called 'my little scorpion' by Vesper One, and believes herself to be credited more for her genius, Isabel plans to be Vesper One Isabel is planning on getting the rest of the Vespers to side her, hence overthrowing and getting rid of the current Vesper One. AWW (AidWorkWonders) later discovered by Dan that Isabel is using it as a cover to travel to places on Astrid's list, aka subduction zones where Vespers are triggering earthquakes and volcano eruptions known as Doomsday.
- Vikram Kabra - Husband
- Ian Kabra - Son
- Natalie Kabra - Daughter (deceased)
- Damien Vesper- Great x 23 Ancestor
Isabel looks very young, and is slightly obsessed with her appearance. She is absolutely ruthless, cunning, and homicidal. She is also trained at espionage. She seems to have a positive attitude, especially when she is about to kill someone. She is the mother of now disowned Natalie Kabra and Ian Kabra. She is also the wife to powerful Lucian leader Vikram Kabra. She can trick people very well and has very bad things up her sleeve if you displease her. She is mentioned a little in the beginning of the series and her character actually comes in in book six, In Too Deep, as a main character. She seems to control Irina Spasky, and she does not appreciate her kids much, even willing to risk their lives in the hunt. Just like Natalie, she loves to shop and is very sneaky. Natalie seems to inherit her traits from her mother. Also, in In Too Deep Irina Spasky was killed by Isabel Kabra's hand although the fire that burned down Alistair's home in which Alistair, Dan, and Amy were staying was meant for Amy and Dan but Irina had a change of heart and came to their rescue.
Fiske Cahill implies that Isabel had some dark experiences in her past that have affected her today. Isabel has always mistreated her children but the Lucian Serum (retrieved by Ian and Natalie in "The Maze of Bones") has seemed to have affected her personality to make her even more manipulative and foul-tempered than before. Irina Spasky says that Isabel used to be one of the best Lucian agents but often did unpredictable, spontaneous things that deterred their cause. She also was selfish to share the Lucian serum and drank it herself.Isabel's cold determination to win the Clue hunt is especially apparent in the tenth book. She breaks down each of the thirty-nine doors of the Gauntlet in the Madrigal stronghold, reaching the remains of Gideon Cahill's lab and all the subsequent labs in which the Madrigals attempted to reunite the family. When Amy, Dan, Hamilton, Alistair, Jonah, Sinead, Ian, and Natalie make it to the lab, Isabel is already there, and blackmails one person from each branch to touch a vial she found to reveal the final Clue. When she forces everyone else to give up their Clues to complete the master serum, she uses several insane methods to force those trapped in the lab with her to give them up, including strapping the people they care about to tombstones rigged with explosives, and threatening to shoot everyone in the room, even her own children, Ian and Natalie (which she does do, halfway) Isabel shoots Natalie in the foot and everyone in the room gives a collective, "That's your daughter! You just shot your own daughter!"
In Too DeepIsabel Kabra first appears as a seemingly harmless old lady (a disguise), but steals Amy's jade necklace and puts her in a cell in the Justice and Police Museum in Sydney, Australia. She talks with Amy for a brief time, and then leaves Amy in the cell. Later, Ian calls Amy to lure her into a trap aboard Isabel's boat. Along the way, Irina Spasky tells Amy that Isabel is dangerous, but Amy ignores her and boards the boat. Isabel starts small-talking Amy, but eventually tells her that Irina murdered her parents. This is, of course, untrue. After Amy refuses an alliance, Isabel tosses rotting fish parts into the water, attracting sharks, and threatens to toss Amy in. She would have been dead, had Hamilton Holt not saved her.
When Shep is flying Amy, Dan, and Nellie to the outback, Isabel drives up in a Hummer to try and stop the plane from taking off. She fails, and resorts to trying to shoot the plane, which also fails.
Later, in the old mine in Coober Pedy where Robert Cahill Henderson (Bob Troppo) used to live, Isabel throws poisonous spiders and snakes into the shaft, nearly killing Amy, Dan, Nellie, and Shep all at once.
Her final heinous act is the same thing she did to kill Hope and Arthur—she burned down Alistair Oh's Indonesian beach house, in which Amy and Dan were staying the night, to take out the pair once and for all. Just when it seems as if Amy, Dan, and Alistair are about to die, Irina Spasky saves them, sacrificing her own life in the process. Isabel treats Irina's death as just a minor inconvenience.
The Viper's Nest
In the last chapters, Isabel has a man bring Amy, Dan, and Nellie Gomez to her. After Amy refuses to give them any information, which, makes her quite mad, she takes Dan and tries to shove him into a spinning propeller. Miraculously, Amy and Dan escape, unharmed. She is left extremely upset.
In this book, Isabel, Ian, and Natalie attack Dan and Amy. Ian goes after Dan but is eventually caught in a net. Natalie and Isabel chase Amy up a waterfall and across a bridge. But on the bridge Nellie throws nutmegs (with Mace, the Clue, on them) at them causing them to slip and fall. Isabel hits her head, and she is knocked unconscious. Amy and Natalie then cooperate to get the Janus icon from Isabel's charm bracelet.
Isabel then appears again following the Cahill children for a box resulting in Lester Dixon's death, putting Dan in a state of shock. At first, the kids decide to go back to Boston, back into the care of Aunt Beatrice. However, thanks to Nellie, they change their minds.
Into the Gauntlet
In this book, Isabel becomes more dangerous than ever. Isabel plants an electronic bug in Amy and Dan 's hotel room. After this event, Ian and Natalie begin to mistrust Isabel.
Near the end of the book on Cahill Island, Isabel threatens Nellie, Mr McIntyre and other loved ones of the family. In the Gauntlet, Isabel blackmails the clue-hunters to give them their separate branch clues. She then shoots Natalie in the foot when she doesn't cooperate. She is also responsible for the huge chasm caused to the players in the Gauntlet.
Just as she is about to drink the serum, Amy tackles her to the ground and then knocks Isabel out with the vial containing the serum . The vial breaks and Isabel is knocked out, but Alistair gives her a pill made by Irina Spasky in order to prevent her from remembering how to make the serum. It is confirmed that Isabel will be in prison for the rest of her life. Ian and Natalie turned on her.
Rapid Fire #4 : Crushed
Isabel is released from prison, and is caught by Ian sneaking into the Lucian wing of their mansion.
The Medusa Plot
It is revealed in the prologue that Isabel has set up a global charity, AidWorksWonders.
A King's Ransom
Isabel finds out that Dan is making the serum. Isabel starts sending texts to Dan pretending to be AJT (which is the initials of Dan's father). She is later discovered that she was pretending to be AJT in Day of Doom.
The Dead Of Night
Ian Kabra comes to meet her at a book signing, to get her attention and inquire about AidWorksWonders. He later finds out that the members are just paid actors by Isabel. Isabel continues to send AJT texts to Dan.
She was posted several times on the Shatterproof's inner front page (Golden Jubilee Diamond) laughing. When Ian tried to contact Amy he mentioned Isabel. Isabel continues to send AJT texts to Dan.
Trust No One
Jake sees her and tells Amy and Dan about a "really well dressed" woman who was "tall with dark hair". Amy recognizes the description was of Isabel Kabra, and realizes capoeirista's whispered message was not "more...a little less...a bell," but actually "Amor to the littlest (Atticus), from Isabel". She was thought by Dan to be Vesper One, but Isabel was actually Vesper Two. Isabel continues to send AJT texts to Dan. Amy and Dan suspect her of being Vesper One.
Day of Doom
Isabel sends a few AJT texts to Dan. Isabel boards a flight to Washington DC where she visits the Smithsonian Museum to view Lewis and Clark's compass. She then takes note of the coordinates on there and alters them to throw Dan and Amy off her trail. She is then pursued by Amy but holds her hostage using hired guards. Dan scares her and the guards away by convincing them the police are coming. She then boards the same train as Dan and Amy to Washington State. She then calls Ian whom she informs that she is dying from poison and orders him to murder one of the hostages. It is revealed she fooled him and is not suffering at all and that she intends to kill both Ian and Natalie. However, she was convinced that Ian was on her (Isabel) side. She then hosts an AWW meeting in which she states she is here to protect the people of the nation from the oncoming apocalypse. She then loses her temper at the lack of the luxury and storms off while Dan and Amy sneak into her cart and reveal that she is AJT.She had impersonated Dan's father and fooled Dan She then takes Atticus and the serum hostage and flees the train heading to the Machina Fini Mundi in The Rocky Mountains. It is then revealed she had no knowledge of the Vesper plan other than where the hostages were and the location of the Machina Fini Mundi. This is due to the fact that she and Vesper One have a hostile relationship and they both want to rule the world. She loses her guards and Atticus and finds out that Natalie is dead. She concludes Vesper One did this and takes the serum. She then storms into the room where the Machina Fini Mundi is and is checking on her dead daughter and attacking Vesper One while preventing Dan and Amy from doing so themselves. She holds Vesper One off from finishing the device, the one thing he cares about while the cave collapses on her, the device, and Vesper One ending her and Vesper One's lives. It is then shown in Amy's dream sequence that she (Isabel) is happily walking with Natalie. Amy claims that though Isabel was ruthless, deep down she still cared for her children.
On the inside cover of Shatterproof, you can see her face on what looks like the Golden Jubilee. If you go to this book's page on the 39 clues website and enter in her name (IsabelKabra) you will get something...I forgot.
Isabel has a talent with codes.
Isabel has extensive knowledge of poisons.
Isabel had one charm on her charm bracelet (the wolf fang) that is connected to the Clue hunt, as shown in Storm Warning.
Isabel drank the Lucian Serum, making her the only living Lucian (before her death in Day of Doom) and third person to drink the serum after Gideon and Luke, thus gaining knowledge about everything strategy, everything leadership, basically everything Lucian.
She is extremely charming, and can make even the toughest Cahill agents spill their secrets without breaking into a sweat.
Isabel's main card is Card 177.
- She never takes off her golden charm bracelet. It features shapes and objects close to her heart and she even once canceled a flight because of it.
- 2 of her cards confirm she's a Vesper—Card 177 and Card 237.
- Damien is stated to have descendants. Isabel may be one, for her maiden name was Vesper-Hollingsworth.
- Isabel has degrees in politics, economics and art history.
- She owns more than 300 pairs of shoes.
- She insists of using bottled water to brush her teeth.
- She hates animals.
- She has been banned from entering Norway, Cambodia, and Zimbabwe.
- She knows how to fly a plane.
- She travels by boat.
- Though McIntyre said that Vespers make Isabel look like Mother Teresa, she was a Vesper herself.
- She is the only known Cahill to succeed in mixing the serum and drinking it, other than Gideon Cahill.
- She is the only known person who has taken the Lucian Serum and the Master Serum.
- She was terrified at Natalie's death, so she drank the serum and killed Vespers. But in Into the Gauntlet, she shot Natalie in the foot.
- She pretended to be Arthur Trent (AJT) to fool Dan into mentioning he had the serum.
- She doesn't care about her children and is like "I give you a 100 dollar bill now get lost!"
- She is always mentioned and/or has appeared, in every book from In Too Deep to Day of Doom.