Lucas Kempton was a businessman, originally from Northern Ireland, and an old acquaintance of Carla Connor who she had met when she was living in Devon between May 2016 and December 2017 as they worked in the same company together. Initially they had clashed as he had an eye for detail which annoyed her but acrimony turned to a strong friendship, but no further as he was deeply involved in a long-term difficult relationship with a self-destructive girl named Lucy, though this didn't stop Carla, thoroughly attracted to him, making a pass at him one evening when she was drunk on Tequila slammers. He rejected her advances with regret and acted as her wingman when she suffered a series of nightmare dates with unsuitable men she had met in Tinder.
By January 2021, Lucas was working for West Place Home and Lifestyle and kept an appointment on their behalf to negotiate an order with Underworld on a deal. Carla was working for the firm again and was taken aback to see him, not realising who he was now employed by their potential client. He explained that the south-west firm was opening a franchise in Harrogate and was looking to do the same on the west of the Pennines, and had thus steered a potential order in her direction after seeing her name on the company's website. Carla was delighted to see him and was pleased to swap stories of their life in Devon, including reminiscing about a pub where she sampled the best gin and tonic she had ever tasted, and was pleased when Lucas pulled a bottle of the Seville orange blend from his bag, inviting her to join him at the Viaduct Bistro where he had booked a table for the two of them for lunch.
Despite some small reservations, Carla accepted the invitation where she was shocked to find out that Lucy had died of a drugs overdose, Lucas not having heeded Carla's warnings at the time that in his dealings with the doomed girl he was trying to fix something that was already broken. In return, Carla kept from Lucas the details of her difficult relationship with Peter Barlow who was then in the depths of his alcoholism.
Determined not to lose another chance, Lucas confessed to Carla that he had booked a spa hotel for the weekend in Lancashire and hoped she would join him. Seeing a respite from the constant turmoil in her life, she accepted and was about to join him when Peter begged her to remain and she did so, telling Lucas that someone was in need of her in the same way that Lucy had needed him.
A few weeks' later, Lucas returned, telling Carla he had set up a meeting with his boss in Harrogate for her to present Underworld's lines to her. He himself would not be present but he did have a meeting beforehand to take Carla through his boss's predilections during which he pushed her to tell him why she was staying with someone as troublesome as Peter. They didn't realise that he was listening at the office door and overheard Carla admit that if she had known what was coming when she first met Peter, she wouldn't have entered into the relationship. As he walked away, what he missed was her assertion to Lucas that the two were bonded soulmates. Peter gave Carla the cold shoulder and she drowned her sorrows with Jenny Connor and Daisy Midgeley, sending Sarah Barlow to Harrogate in her place, but without telling Peter. They gained the contract and Lucas walked into the factory with the good news when Peter was confronting Carla about her whereabouts the night before, as he knew that she hadn't made the trip. Peter gave him the frostiest of welcomes, and later Lucas found out that he was the possible cause of the problem. He offered to talk things through, just as mates, but she refused the offer.
The years of damage that Peter had inflicted on his liver resulted in March 2021 in him suffering a bout of hepatic encephalopathy, a decline in brain function that occurs as a result of severe liver disease which means that toxins cannot be successfully removed from the blood. Initially undiagnosed, all of his family and friends put it down to him drinking again and Lucas offered Carla a shoulder to cry on and a diversion from her troubles with a trip into Manchester. As Peter's condition deteriorated, Lucas put his cards on the table and, telling her that he loved her, asked her to come back to Devon with him. Having reached the end of the line, Carla visited Peter in Weatherfield General and told him she was bailing out on him. Their tearful conversation was interrupted by the doctor who rocked Carla with the diagnosis and proof of Peter's innocence. She therefore told Lucas that she wouldn't be going with him and had realised that she would simply be running away from Peter and not through wanting to be with Lucas as a specific alternative. Undeterred, Lucas visited Peter and had a calm but very direct conservation with the recovering patient, asking him to let Carla go. Lucas made it clear that he thought Peter was a lost cause and that Carla felt trapped with him. Peter retorted that he loved her but Lucas made a pointed jab that Peter didn't even love himself and dropped a bombshell that her friends thought she should leave him, having had a specific chat with Steve McDonald on the subject. The two men parted on bad terms and having worked out that Steve was the person in question, Peter fell out with his brother-in-law.
His business with Underworld caused him to visit the street on several more occasions resulting in more confusion. Tyrone Dobbs has started a secretive affair with Alina Pop. When Alina's flatmate Emma Brooker witnessed some mild flirting between Lucas and Alina, she assumed the two were something of an item, particularly when she walked into their flat and saw a pair of men's jeans on floor and knew that Alina was with someone in the bedroom, not realising it was Tyrone. Happy to keep up the deception, Alina did nothing to correct Emma's error but word got back to Maria Connor who had been cutting Lucas's hair in Trim Up North at the time in question. She suspected something was going on with Tyrone and this matter confirmed her suspicions though she chose not to tell Tyrone's partner, Fiz Stape. It was only a few days later that Fiz herself saw Alina and Lucas chatting together again in the street and made comment on their relationship, puzzling him and forcing Alina to come clean.
By the end of May, the order that Lucas had put in was ready and delivered but Sarah became suspicious when payment was late. Carla at first defended her friend but when she checked with West Place Home and Lifestyle, she found that they knew nothing of the order and Lucas had left their firm three weeks before. Sprinting into action, Carla and Sarah drove to the delivery point at a factory unit on the Burnside Industrial Estate in Manchester where they jemmied open the door and retrieved their stock.