The only A scenario considered to be canon, is Claire A. The canon B scenario is Leon's.
In the Streets of Raccoon City
In the opening sequence we see Claire Redfield riding into Raccoon City on her motorcycle. Claire, who is the younger sister of Chris Redfield (one of the S.T.A.R.S. members who survived the Mansion incident) has traveled to Raccoon City to find her brother. Upon her arrival, Claire notices that the city is unusually desolate. She arrives upon "Emmy's Diner", which appears to be empty as well, but she soon learns differently when she is suddenly attacked by a Zombie. Horrified, Claire attempts to flee the diner, but finding her escape route blocked by the walking dead, she makes a break for the emergency exit. On the other side of the door she is met by Leon S. Kennedy, another survivor, who aims his gun at her, Claire pleads with him to not shoot, but he tells her to duck so he can dispose of the zombie behind her.
Together, Leon and Claire run down a back alley as they try to escape the zombies. When they emerge from the alley they spot a poilce cruiser and promptly use it to escape. This attempt fails, however, as yet another zombie emerges from the back seat. In the ensing struggle, Leon loses control of the car and crashes it head-on into a lamp post, the momentum flinging the zombie violently through the windshield. At that point, they catch a glimpse of a semi-truck bearing down upon them and escape the wrecked vehicle, just seconds before impact. The resulting explosion separates the two, but nevertheless, they agree to meet up again at the police station.
On her way, Claire seeks refuge inside the Kendo Gun Shop and discovers upon a third survivor; the owner Robert Kendo. She asks him what has happened to the town, but he's just as clueless as she is. Only moments after Claire speaks to him, zombies break into the store and attack Robert, who is quickly overwhelmed by the horde. Escaping through the backdoor of Kendo's gunshop, she pushes through alleyways crammed with zombies until finally reaching the front gates of the police station.
Raccoon Police Department
Upon entering the large building, Claire finds that most of the doors in the main hall are electronically sealed, but one is suspiciously unlocked. Inside she finds a wounded police officer (Marvin Branagh), who tells her about Chris and his teammates' involvement in the recent Mansion incident two months earlier, and how nobody believed their story. He then hands her a keycard to unlock the doors in the hall and tells her to go and rescue the remaining survivors. Claire hesitates to leave him, but when Marvin points his gun at her, she realizes she has no choice. Promising to check back on him soon, Claire proceeds cautiously through the halls of the precinct and soon encounters a horrific new creature called a Licker, which seems to be an evolved form of a zombie. Eventually, she manages to locate the S.T.A.R.S. Office and finds Chris' diary, which reveals that he had left for Europe a month prior to her arrival. She then exits the room to find a zombie menacing a little girl, who runs away and escapes through the ventilation shaft. While pursuing her, Claire finally meets up with Leon, who agrees that they should find and rescue the girl. He also gives Claire a radio, so that they can keep in touch.
As her search continues, Claire finds the flaming wreckage of a helicopter which crashed into the building from the second floor, and is now blocking the hallway. After successfully extinguishing the fire, she searches for a way to remove the debris and finds a block of C4 in the evidence room, but is lacking a detonator. Retracing her steps back to the room where she encountered Marvin, she finds he is nowhere to be seen. In a small side-office, she sees a detonator on the desk and Marvin slumped against the wall. As she moves to take the detonator, Marvin suddenly rises to his feet and degenerates into a zombie right before her eyes. She quickly grabs the detonator and either running away or killing him.
With the detonator, she manages to clear the wreckage and enters the police chief's (Brian Irons) office. Startled by the intrusion, Irons points a gun at Claire, but is relieved to find that she is human. Claire attempts to question him, but she can't help but notice the unconscious woman sprawled across his desk, clad in a bloodstained white gown. The Chief identifies her as Mayor Michael Warren's daughter, whom he was told to look after "but failed, miserably". After lamenting her beauty, he confirms that she, too, will become one of the walking dead. Only by putting a bullet through her brain or by complete decapitation can the process be stopped. He looks towards his old taxidermy items somewhat regretfully, and shakes his head at his former hobby. He then asks Claire to leave.
Proceeding through a corridor into the next room, Claire hears the sound of footsteps running away from her. She follows them into a back room, turns on the light switch and discovers the little girl who, despite being cornered, still attempts to flee. Claire grabs hold of her arm and manages to calm her down, insisting she's not a zombie. The girl bursts into tears and embraces her as Claire updates Leon of her status on the radio. She learns that the girl is 12-year-old Sherry Birkin, the daughter of two researchers working for the Umbrella chemical plant in Raccoon City. She explains that her mother told her to go to the police station because it was too dangerous to stay at home. Knowing that the precinct is far from safe at the moment, Claire advises Sherry to come with her. The girl hesitates, hinting that something "much larger than any of those zombies", is hunting her. A vicious groan is heard somewhere nearby, causing Sherry to run off in a panic.
Claire makes her way back to the Chief's office, only to find that both he and the Mayor's daughter have mysteriously vanished. She takes a key from the desk and notices a diary on the chair, which details Irons' corruption towards the officers and the city, having seemingly developed a sick passion for hunting the survivors in the precinct. Claire then heads to the precinct's underground level, where she encounters Sherry once more. Although Claire strongly suggests that they leave this place, Sherry refuses, insisting that she heard her dad call her name somewhere. Sherry acts quickly, and climbs up and through a ventilation hole. After wandering an industrial-looking area on the backside of the police station, she fails to find her father, but instead finds some things that Claire could have use for. She returns to the room with the ventilation hole, but explains to Claire on the other side that she can't reach the hole anymore and is going to have to find another way back.
The two reunite in the Chief's office again, after Claire had discovered a secret passage behind Irons' desk. Claire, sensing danger, decides to go down the elevator alone and instructs Sherry to wait for her in the office. In a dim, torchlight passage, she hears a frightened man yelling for help. In the next room, she is startled to find an agitated Chief Irons, who once again threatens her with a gun. When Claire confronts him about the writings in his journal, he reveals his co-operation with Umbrella, as well as some other information on the G-virus. The Chief also implicates William Birkin in the conspiracy, and informs Claire that Sherry is in fact his daughter. Outraged by Umbrella's "betrayal", the Chief aims his gun at Claire, vowing that no one will leave the city alive. Before he can pull the trigger, however, an intense pain causes Irons to double over as a G-parasite bursts out from his chest, killing him instantly. A horrific creature (later discovered to be William Birkin, or "G") had implanted him with one of his G-embryos, but Irons' body had rejected the parasite, which quickly escapes down into the nearby sewer tunnel.
After chasing it down into the sewers, Claire discovers that the G-embryo is fast to evolve into a large, deadly creature. She eliminates it with a barrage of firepower, and then heads back up to Irons' office to retrieve Sherry, figuring that they have finally secured a way out of town through the sewers.
Shortly after entering the sewers, they discover that "G" is in pursuit of them. They manage to escape its notice, but are separated as a sewer drainage hatch opens and sucks Sherry down. Sherry attempts to make her way back to Claire, by going through a ventilation hatch in a nearby room. On the other side of the hatch, she finds herself standing on a garbage disposal platform. Noticing something glinting on the ground, she bends down and picks it up. At that point, the garbage disposal platform opens up, and she, along with all the garbage, falls down into a pool of water. G manages to find her, and implants her with his embryos. Before losing consciousness, the last thing Sherry manages to do is to call out Claire's name.
Meanwhile, Claire pushes further into the sewers where she is confronted by Annette Birkin. Annette accuses Claire of being a spy having been sent here to "collect the sample" from her husband. Claire deduces the woman to be Sherry's mother and warns her that Sherry is in serious danger. Annette is devastated, wondering why Sherry is here rather than in the police station, and says that William will be after her if she is nearby. She then tells the story of how it came to be that William was injected with the G-virus, and how Umbrella's team had been sent in to steal the sample, thus resulting in the accidental leak of the t-Virus which the rats ingested. Annette explains that the giant creature wandering the precinct is William himself, and that his sole purpose is reproduction and that this is why he is after Sherry. Annette informs Claire that it's impossible for Sherry's body to reject the embryo due to their father-daughter genetics. Shortly thereafter, both of them hear Sherry scream, and decide to split up to search for her.
Making her way through the sewers, Claire finds the room where Sherry landed. Before she can get to her, however, a gigantic mutated alligator lunges out of the water and attacks Claire. After defeating the alligator, Claire reaches Sherry and is able to wake her and lead her out of the sewer. They soon activate a platform which proves to be a direct route to Umbrella's underground research facility. Their passage does not go unhindered, however, as Sherry loses consciousness due to her infection, and a furious William has caught up to them. Claire confronts him and is able to subdue him as the platform halts at its destination.
Umbrella Research Facility
Claire realizes she doesn't have much time before Sherry's embryos pupate; she knows she must find a cure. She takes Sherry to the security office and leaves her there to rest. The two exchange some emotional words, before Claire proceeds further into the lab. Her first objective is to succeed in locating the main power fuse, so that the lab's power is restored. Proceeding further down into the lab, she runs into Annette once again, who is furious for what Claire has done to William. Fearing that her husband is dead, Annette intends to return to favor by killing Claire, but is overjoyed when she hears William's ferocious roar nearby. Showing no concern for her own safety, she approaches her husband's monstrous form, only to be greeted with a fatal swipe of his claw. In her last few breaths, Annette gives Claire all the information required to cultivate the vaccine DEVIL for Sherry, and expresses regret that she wasn't a better mother. As she succumbs to her wounds, the self-destruct system is mysteriously activated, leaving Claire no time to mourn.
By pure coincidence, Claire happens to witness Leon entering the lab through one of the surveillance monitors, and contacts him to ask for his help. Realizing she would never have enough time to gather the necessary parts for the vaccine, cultivate it and pick up Sherry, she asks Leon to do the latter. Leon is concerned for what she is about to do, but does as he's told.
Meanwhile, Claire gathers the necessary components and succeeds in creating the vaccine. As she enters the elevator room, awaiting its arrival, she is confronted by William in his near-final form. With only a few minutes left before detonation, she has no choice but to defend herself against Birkin.
With the monster presumably dead, the elevator arrives just in time to allow Claire's escape via the emergency tunnel at the bottom platform. Aboard the train, she reunites with Leon and Sherry and is able to administer the vaccine, thereby eradicating the development of the G-virus within Sherry's body. Claire lets Sherry keep her prized pink vest, and implies that her goddess has succeeded in protecting Sherry. At the end-sequence of this scenario, Claire and Sherry embrace in a warm hug.
- When Claire finds Leon through the security monitors, Leon's bandages from his wound are not seen, but they were present in the ending.
- There is a logic error concerning Sherry's locket in this scenario: In Leon B, when Ada climbs through the shaft to get Leon the fourth precinct key, she runs into Sherry who flees from her, losing her locket. However, here in Claire A, you'll notice that the locket is already missing by the time you play as Sherry to get Claire the same key, which must have happened earlier because Sherry is unable to get back up to Claire in the end, and therefore can't have met her after meeting Ada.