Not much is known about her, but she was a good student once - being listed on a notice board as a star pupil - until something happened, likely becoming a werewolf. Christa is seen to be a loner who thinks of herself as a freak and whose parents seemingly don't understand her. She received the werewolf curse when she was scratched on her; left upper arm, left forearm and on the left side of her stomach, by an unknown werewolf during a full moon.
Usually when a full moon occurs, she uses a rubbish shoot at her home which leads to the basement and sneaks out when the rubbish is collected the next morning. Like other Werewolves her greatest worry is that when she transforms she will kill her family.
Along with Adam she is hunting for Matt's killer. However, this is complicated by the apparent 'triangle' that is developing between the three, Matt
having revealed that he had feelings for Christa when he was alive and Christa's reflections in a diary implying that she has some kind of feelings for Adam even if she rejects them.
The Murder hunt begins after Mr Swan gives her and Adam detention for swearing at him (believing Swan to be Matt, who had been constantly following her, and Adam for trying to cover Christa's actions - so she & her don't get found out). In detention, she becomes irked that her "stalker" (Matt) is there as well, however Adam points out he is in fact dead, and the two of them can see him because he's a Vampire and she's a Werewolf to which Christa promptly denies. After talking to Matt about his murder the trio agree to help him pass over to the other side by investigating him murder themselves. Later it is found Matt died in the gym toilets, where he suspects Danny Curtis as his killer - who had been bullying Matt for years. (Episode 1)
The gang go on to question Danny about Matt's murder trying to get him to confess, however he was found to be innocent as Matt was intent on using Adam and Christa as his own hit men to enact revenge on those that bullied him, starting with Danny. Due to Matt's actions, she gives up on trying to find his killer. (Episode 2)
Some time after she along with Adam are ignoring him until he recounts he died by drowning (that he just remembered) in the gym toilets. Hearing this she proposes a search for finding Matt's body in hopes of it jogging his memory and remembering more. He later reveals he was hiding in the toilets after being caught looking through a grill at Brandy in the girls changing rooms (also seeing Christa's wolf scars as she dresses). to which Brandy chased him to the toilets and proceeded to drown him. When it is suggested Brandy Mulligan is to blame for Matt's death, she dismisses it as unlikely. (Episode 3)
The next day she meets Brandy by the school bins and questions upon the disappearance of Matt, however Brandy is convinced this small talk is simply a cover for her meeting a boy, to which Adam soon shows up presenting himself as Christa's new boyfriend. Believing Brandy to be the murderer the gang decide whether or not to go to the police, thinking they will just laugh at them. When Adam starts talking about how he wishes to personally dispense justice for Matt by feeding on Brandy, Christa firmly believes it is more about him wanting her drink her blood. Adam rebuffs this telling her to "man up for God's sake" believing it to be the right thing to do. Christa goes on to try and stop him killing for Brandy's and his own sakes but to no avail. He is only stopped when Matt finally admits Brandy left before finding him and that he wasn't looking at Brandy at all, he was in fact looking at her. (Episode 4)
Sometime after Matt gives her a love letter containing his feelings for her and that his last act was to graffiti a toilet wall with "I [i]Heart[/I] Christa". As Adam comes into the science/detention room with his patented style of bravado, the pair talk about a public break up (with Matt hiding behind the back desk), due their interactions in front of Brandy, it has become school knowledge that Christa and Adam are an item. It is here Mr Roe informs them of Mr Swan telling him to clean and bleach the gym toilets. Later that night Adam, Christa and Matt meet in the toilets discussing Swan's motive for murdering Matt, as she and Adam leave, Swan catches them - believing they just had sex. Christa meanwhile realises the school CCTV cameras will show who the killer is. That night they enter the school security room, only to find the necessary tapes missing. Empty handed they leave with a map that show the locations of the CCTV cameras. (Episode 5)
The trio identify the cameras with missing footage, Crista punches Matt in return for a rude comment and still in denial about her being a Werewolf. When in the gym she immediately notices an odd smell thinking Matt or Adam have farted to which they have to make a hurried attempt to hide in a vaulting horse. When Swan beings to show his aggression against a punching bag, Christa marks this as a sign of guilt but Adam believes it to be circumstantial evidence, to which she grudgingly agrees. Then after commenting how they need proof or Matt won't be able to pass over, Matt unexpectedly moves the vaulting horse - attracting the attention of Swan. When he lifts the top off the horse up, to his annoyance and Matt's unwelcome surprise, Swan finds her and Adam embracing and kissing each other. Back in detention, Christa realises Matt moved the vaulting horse on purpose - Matt beliving she and Adam want to be alone despite them knowing of his love for her. During this Christa comments how she didn't want to kiss Adam. (Episode 6)
She and the boys decide to hunt for Matt's body after school, just before a full moon - going on advice from George that her senses will be at their highest - Adam attempted to create a 'trail' for wolf-Christa to follow after finding Matt's body in the school. However unbeknownst to them, Mr Rowe locks the Gym doors, just as Christa starts to transform.
Quick thinking from Adam tempted her into the gym's equipment locker (which was barricaded behind her), where the next morning Matt's body was discovered. (Episode 7)
The murderer was subsequently revealed to be Matt's old teacher, Mr Rowe, who had become enraged at the irreverent way he was treated by his students, Adam almost attacking him before Christa talked him down. Rowe was subsequently thrown through Matt's door when he tried to attack Adam and Christa to protect his secret. (Episode 8). At the end of the first series, she finally accepts (as does Adam) that the three of them are friends and enjoy hanging out together.
At some point after solving Matt's murder, Adam apparently went separate ways from Christa and Matt. (Hold The Front Page)
According to Rook's emails, during her monthly transformation on 29 October, 2012, Christa in her transformed state killed two youths who broke into the disposal unit where she transformed. Beyond distraught at the incident, Christa afterwards ran away without a word to her parents. She travelled as far away as Scotland before the Department of Domestic Defence lost track of her, although reports suggest that she is currently living on the Isle of Grimsay. Her status following the Devil's victory is unknown however.
- Adam: First meeting at the school cafeteria, the two at first didn't see eye to eye. Even though they worked together while investigating Matt's death, they still had a slightly antagonistic relationship. However, through Christa working as his moral constraint and Adam at times making her laugh through his humor, the two developed a friendship that had hints on a romantic one, which Matt suspected. Adam left the group soon afterwards and married Yvonne Bradshaw. According to the Department of Domestic Defence, Adam and his wife Yvonne are on their way to Northern Scotland in 2012, where Christa is supposed to be living at that time.
- Matt: Prior to the case of his murder, Christa was unaware that Matt harbored a three year old crush on her. During the time she didn't know he was dead, Christa believed him to be a stalker, but soon accepted him after she learned he died. During the case, she and Matt had an uneasy relationship as Matt continuously withheld information from her and Adam. Upon learning of his crush, Christa was slightly flattered, but told Matt that they were only ever going to be friends. After solving Matt's murder, the two have seemed to develop a good friendship despite Christa being slightly annoyed sometimes. According to the Department of Domestic Defence Christa ran away after killing two boys while transformed. Matt is not mentioned, but the DoDD has difficulties spotting ghosts, so it is unknown if he went along with her.