Kailey Clark is a woman who resides in Holby.
Sometime after Kailey took custody of Frankie and Storm, her mother left them, leaving her to take care of them on their own. Lee began to harass Kailey over the phone demanding her to allow his children to visit him. She eventually caved under the pressure and told Frankie about their arrangement. Terrified of seeing Lee again, whilst Kailey was in the shower, Frankie left the flat and ran away to Toucan Towers, a disused play area she loved to visit when it was still in operation.
On 6 July, the day after Frankie's disappearance, paramedic Iain Dean, who was her call handler during the fire, visited Kailey to investigate the circumstances behind the situation. He asked her if Lee was culpable in his disappearance, but she denied that he was and recalled him telling her that "being a mum [did not] occur naturally" to her. After finding a happy photograph of Frankie at Toucan Towers, Iain decided to go there and found her unconscious and hypothermic. She was subsequently rescued by the fire service and taken to Holby City Hospital's emergency department for urgent treatment.
In the relatives room, Kailey apprised Iain of Lee's constant harassment and maintained her insubordination caused him to hurt Frankie. Iain explained that Frankie ran away because she was scared and specifically went to Toucan Towers as she had happy memories of them there, and Kailey's confidence in her aptitude as a mother began to restore. However, consultant Ethan Hardy soon informed her that Frankie was haemorrhaging internally. Frankie was rushed back into resus where she went into PEA. When the medics managed to stabilise her, Kailey hugged Iain in relief, and Lee, who had recently arrived, pulled her away. When Lee started disparaging Kailey's parenting skills, Iain confronted him about his abuse of his children and pinned him against the wall after he suggested that he had perverse ulterior motives.
Later, Iain's sister Gem returned Storm to Kailey after she took care of her. Kailey told her that everybody thought that she was incapable of being a mother, but Gem opened up about her issues with self-confidence in the past and encouraged her to be herself. Iain backed her up and brought his recent mental health struggles. Inspired, Kailey admitted to herself that Iain was right about Lee. On the first floor, Lee returned after complaining to Jan Jenning about Iain's conduct, and Kailey scolded him for caring more about his "bruised ego" than his own daughter. When they were granted permission to visit Frankie, Kailey prevented Lee from following her and demanded him to drop the complaint. She pledged to give her daughters "the future they [deserved] without him". (CAS: Series 33, Episode 42)