Denton was born on the 12th April 1976 to Elizabeth Denton and an unnamed father. Whilst working in Crime Audit, she entered into a brief relationship with DCC Mike Dryden, becoming pregnant with his child. He later pressured her into having an abortion and stopped seeing her, resulting in her having an obsessive disdain toward him.
Prior to the events of Series 2, her mother became increasingly ill and had to be taken into care at Ashcliffe Nursing Home. In order to afford the fees, Denton sold both hers and her mothers house and moved into a smaller terrace. Medical records show her address as: 31 Harpur Street, Haneast, B17 0KW.
Denton joined Central Police in 2000, where she trained at Ryton-on-Dunsmore Police Training Centre, obtaining additional training in Data Analysis. As a Constable, she worked in the Missing Persons Unit at Polk Avenue Station in 2000. Upon promotion to Detective Constable in 2003, she worked in TO-9 at Hillside Lane Station. In 2008, after being promoted to Detective Sergeant, she worked in Crime Audit in Kingsgate Station, Upon promotion to Inspector in 2010 she remained at Kingsgate Station, but was transferred to Specialist Economic Crime. In 2011 she was transferred to the Criminal Investigation Department at 4th Street Station.
Denton is first introduced as the duty Inspector at 4th Street Station on the night of September 5th 2013. After receiving a call from DS Jayne Akers from AC-9 Witness Protection regarding a credible threat to the life of a witness, she attempts to contact her superior, Chief Superintendent Raymond Mallick to authorise an extraction. Unable to reach him, she then calls up to Deputy Chief Constable Mike Dryden, who authorises the op, much to the objection of Sergeant O'Neill. Taking PC Vincent Butler and Sergeant Alex Wallis with her, Denton makes her way to the safe house.
Arriving at the safe house at St. James Close, Denton has Akers and the witness, Tommy Hunter, take a second car with the uniformed officers, whilst she leads alone. When Denton takes a surprise alternative route back to the station, her car is forced off the road, and Akers vehicle crashed into head-on. The impact deploys the airbags, which incapacitate the uniformed officers in the front. Shaken, Denton urgently calls for backup. Two masked gunmen (later revealed to be corrupt officers DS Manish Prasad and DC Jeremy Cole) emerge from the vehicle, and after shooting dead Butler and Wallis open fire on Akers and Hunter. After being shot, the two gunmen then douse them in petrol and set them on fire before making off. A shaken Denton then emerges from her car, and puts out the fire on Akers body.
After being taken to South Central Hospital with Akers and Hunter, Denton sits in shock as Akers is pronounced dead. She is questioned by Chief Superintendent Raymond Mallick, but does not answer, instead chastising him for not responding to her request. Upon returning to 4th Street Station, Denton is assaulted in the toilets by Sergeant O'Neill and the rest of the staff, who blame her for the deaths of their colleagues. She is then called into AC-12 to be interviewed as a witness to recount the events of the ambush, where she is represented by her federation rep Detective Inspector Samuel Royal. During the interview, it is mentioned by DC Georgia Trotman that Denton had previously reported a two colleagues for breaches of conduct, both of which were upheld. However, when DS Steve Arnott and Superintendent Ted Hastings begin to question her regarding the choice of route that led to the ambush, and suggest she would be susceptible to bribery due to her financial situation, Royal has the interview terminated. Denton then chastises AC-12, claiming they are trying to twist a case out of her misfortunes. Back at 4th Street Station, DC Kate Fleming joins the Missing Persons Unit undercover as DC Kate Foster. Later that evening, in Denton is irritated by her neighbours loud music.
Denton is seen attending DS Jayne Akers funeral.
Denton is assigned to the Missing Persons Unit, to monitor cases on 28 day review by Mallick. She believes this lackluster posting is retribution for her not covering for him the night of the ambush, and claims she will be taking it to HR. Whilst scrolling through the Central Police Portal at missing persons, she stops briefly on the page of Jackie Laverty, before focusing on the page of Carly Kirk. She then pays a visit to Bob Carson and Tessa Carson, Carly's foster parents. Back at the station, she is met by DS Steve Arnott and DC Georgia Trotman, who want to ask her more questions. Although initially apprehensive, she eventually talks with them regarding the behaviour of DS Jayne Akers the night of the ambush.
Denton confronts her neighbour, Lorna Barratt, who is playing loud music. Before Barratt can even finish asking her what she wants, Denton hits her on the side of the head with a wine bottle, then repeatedly bashes her head against the floor shouting "I will not take this anymore!" She then walks off, wipes down the botttle, and throws it in a neighbours wheelie bin. Back at the station,
Denton leaves 4th Street Station, claiming to be going on a personal errand. DC Kate Fleming follows her discreetly. She firsts pays a visit to her mother, Elizabeth Denton, at Ashcliffe Nursing Home, and then enters payphone booth to make a call. Fleming has police Telecommunications trace it, and it transpires that Denton called the Intensive Care Unit of South Central Hospital, where Tommy Hunter is being treated. Not wanting to blow her cover early on, Fleming has DS Steve Arnott and DC Georgia Trotman go to the hospital, and returns to the station before Denton gets back. The episode ends with Denton cautiously staring at Fleming from her office, before closing the blinds.
Denton is informed by Mallick that Lorna Barratt, her neighbour, has complained about Lindsay attacking her to professional standards. Denton denies the charges, claiming Barratt has a long history of alcoholism and mental health problems and is making it up. She also has DC Kate Fleming (known to Denton as DC Kate Foster) act as a witness to Mallick's accusations. She then warns Mallick she intends to clear her name, even if it means dragging all her colleagues through the courts. That night she returns to her neighbours house to again complain about the loud music. Barratt threatens to sue her, then says if Denton pays her £100 she will keep it down. Denton refuses, giving her only £10, which Barratt begrudgingly accepts.
She and Fleming pay a visit to The Queens Arms, where a friend of Carly Kirk named Michelle works. During their questioning, Michelle reveals that Carly had an Asian boyfriend named Matt, who was nearly twice her age. The two then make their way to revisit the Carsons, Carly's foster parents, and Denton enters their address into the sat nav in her car. When Kate attempts to gain Dentons trust by offering to cover for her regarding the assault on Lorna Barratt, Denton fakes concern at her offer to lie. Later, she accosts media manager Jo Dwyer outside Pelbury House and asks her to publicise the disappearance of Carly Kirk, but is brushed off. Back at the station she meets with the Carsons, and sadly informs them that there will be no press conference regarding Carly's disappearance due to "insufficient interest". Although Bob Carson is understanding, Tessa Carson becomes angry at the fact, and blames Denton before storming out.
That night, Denton receives a surprise visit from Fleming at her home in Haneast, who brings a bottle of wine as a "peace offering" for her previous mess up. The two briefly talk, but as Fleming moves to leave, Denton becomes more open in her suspicion towards Fleming. Edging close, she demands to know the worst thing Fleming has ever done. Fleming tells her it was covering up the real reason behind a man's death, but Denton doesn't believe her, pressuring further. Fleming leaves without answering the question. The same evening, she enters Lorna Barratt's house through an open door, and turns off the music whilst Barratt is asleep. She notices a chip fryer has been left on, and briefly considers allowing a fire to break out before turning it off. Before leaving, she takes the £10 she previously gave Barratt from the coffee table. The next day, Denton is seen handing financial records requests for DS Steve Arnott and Superintendent Ted Hastings. She gets an oblivious Chief Superintendent Raymond Mallick and another senior officer to sign off and authorise them, under the guise of them being related to her missing persons investigation.
She later asks Kate personal questions related to her police record (which has been falsified since she is undercover), but Fleming does not falter or give away she is undercover. Denton then makes a call to A. Ashlon & Sons Service Centre, believing Kirks boyfriend may have worked for them. However, she later makes her way to the abandoned lot of A&B Carriage Repair on the Canalside Industrial Estate, and asks Fleming to join her. When Kate arrives, Denton punches her in the stomach, having deduced that she is AC-12, and leaves after taking her phone. She is later shown playing the piano in her house over the sound of Lorna Barratt's music.
After DC Kate Fleming reports to Superintendent Hastings her cover has been blown, AC-12 bring Denton in for a second interview under a Regulation 15 Notice to question her as a suspect. DS Steve Arnott begins to pick apart her previous statement regarding her being unable to get accurate travel information the night of the 5th September Ambush. Fleming adds that Dentons service car is fitted with a Type 60 Travel System, which provides such information and that she had seen her using with no problem whilst undercover. Denton denies this, claiming in the stress of the situation she forgot to look at the sat nav. She confirms making a call to South Central Hospital from the phonebox, but not the one that asked for Claire Tindall by name. Nevertheless, Superintendent Ted Hastings charges her and places her under arrest.
However, whilst still on tape, she reveals the information she has obtained on all three of the officers. This includes: compromising photographs of Arnott sleeping with Claire Tindall, records that show Hastings is in considerable debt due to a investment gone wrong (and has not declared it) and the fact that Kates mobile phone has "interesting" call history on it (such as the call from Richard Akers the night of the ambush). However, despite her power play, she is still remanded in custody. However, before she can be removed from the AC-12 Building, two couriers from Package Fast deliver the classified documents from AC-9 Witness Protection, which reveal that Tommy Hunter was the witness. Denton asks Steve about who the witness was, but he does not answer. Before being locked into a custody cell at Hillside Lane Station, she professes her innocence once again to Arnott.
Denton is escorted from Hillside Lane Station to Crown Court by dock officers from SecuritVite. The prosecuting counsel, Ms. Latimer, recommends that bail be refused due to belief that as a police officer Denton has the means and knowledge to abscond. Despite the defence counsel, Ms. Anderson, applying to the contrary, the judge refuses to grant bail. She is told she will be held until the 18th November. Shocked at the news, Denton immediately voices concern for her cat, Bella. A SurePen transport van then transfers Denton from court to HMP Brentiss, where she is booked into custody by Offender Management Officers Jenny Leland and Alison Merchant. Later that day, she is served food which has human excrement mixed in with it. She is shown vomiting in her cell toilet while the two guards watch in amusement.
DC Kate Fleming later visits her in prison to ask her further questions, mainly if she knew that the witness was Tommy Hunter. Denton denies any knowledge of Hunter. Fleming then asks why she kept quiet in the interview about Fleming receiving a call from Richard Akers the night of the ambush. Denton replies that she didnt have to, and that Kates actions are her "ticket out of here", as it will all come out in the trial which will paint a better picture of innocence upon her. A brief scene is later shown of Lindsay in her cell, consumed by the noise of neighbouring prisoners bashing their cell doors and yelling obscenities directed at her.
After a body is found buried under the abandoned lot of A&B Carriage Repair, DC Kate Fleming returns to HMP Brentiss to interview Denton about why she was at that location a few days prior. She draws attention to the fact that the same men who carried out the 5th September Ambush and threatened Claire Tindall utilised the unit, and that Dentons presence there cannot merely be a coincidence. Denton admits that it appears that way, but still denies any connection. She then learns that the body found was that of a 15 year old girl, who had been strangled then mutilated to prevent identification, but believes it may be Carly Kirk. However, after asking if DNA from the body can be compared to control samples of Carly's, she is told that the samples cant currently be traced due to an admin glitch.
Becoming emotional, Denton asserts the only reason she is in prison is because she answered DS Jayne Akers phone call, and did what "any decent police officer" would have done in trying to help her. Fleming fires back claiming she also picked up a payphone to call South Central Hospital and ask for Claire Tindall by name, which amongst other evidence is why she has been imprisoned. Denton then admits she did make the call to the hospital, but only to see if Tommy Hunter had said anything that could prove her innocence, which Kate does not believe for a second. She goes back to saying how she wasn't even meant to be on duty that night, but was covering for Inspector Joseph Barlow, and that she often did so for other officers with families in an attempt to get along. Denton then says she is happy to amend her statement regarding what she has just said, but only if Kate will do the same and disclose the phone call she received from Richard Akers the night of the ambush.
Whilst exercising in the gym at HMP Brentiss, Denton is attacked by two other female inmates who attempt to crush her hand with a weight. However, the fight is broken up by Leland and Merchant before any damage is done. The two officers take her into their break room, where they appear sympathetic and offer to make her a cup of tea, in addition to promising to "deal" with the two prisoners personally if she doesn't report the incident. However, Merchant then pours boiling water over her hands, and warns a screaming Denton to stop talking to AC-12. When DC Kate Fleming visits her a third time, her hands are bandaged and in slings, and she mentions she has been referred to a burn specialist. When Fleming tells her that due to a legal suppression order, her call history cannot be entered into evidence, Denton becomes enraged, her leverage against Kate gone. It is also revealed that CCTV of the attack on her has "gone missing", and the guards have convinced her attackers to testify she burned her hands as an act of self harm (and the guards tried to stop her). Believing she is being set up as a patsy, Denton tells Kate she believes someone with executive level authority, DCC Mike Dryden, is responsible. When Fleming dismisses her theory, she goes on to explain her and Dryden had an affair, but he broke it off to remain with Helen Dryden. Fleming once again dismisses her, believing she is guilty and is only mentioning such information now to get revenge on Dryden and tie the AC-12 investigation in knots.
Once Fleming departs, Denton tries to sleep in her cell whilst her neighbouring prisoners slam on the walls chanting "bent bitch". Her claim that she and Dryden were involved romantically is proven to be true, with Fleming discovering the two of them worked together in Crime Audit out of Kingsgate Station when she was a DS and he was a Chief Superintendent. Lindsay is then seen being escorted into the shower block by Jenny Leland and Alison Merchant, who inform her that she must shower alone. Before getting undressed, she considers the dire situation she is in, and contemplates rushing the two guards. However, she comes to her senses, and quietly affirms her desire to prove her innocence. The episode ends with DS Steve Arnott paying a surprise visit to the prison, telling her he believes her.
After being granted an appeal trial, and is acquitted on the basis of an improper sexual relationship with Arnott.
After refusing to accept a bribe, she is murdered by "The Caddy", a corrupt officer. Prior to her death, Lindsay discovered crucial evidence pertaining to the Danny Waldron murder investigation and historic child sex abuse, which she sent by email to AC-12 as her final act.