Cleo had a rare mutation to the Fox-03 gene, linked to a longer life expectancy.
After attending Lydia Tyrell's birthday party in November 2019, Cleo, Isobel, and their chauffer Arkady went missing. Days later, Cleo and her mother reached the spot where they were to meet Malak. However, Malak was late and two men and a woman attacked the mother and child. Isobel urged Cleo to close her eyes as she quickly incapacitated the group. Malak finally showed up soon after.
Malak led them to an underground community and introduced them to "the Lung." After Cleo's mother disguised them, the Lung prepared them for a venture out of the city, during which they would be escorted by "the Bones."
Former Blade Runner Ash soon arrived to retrieve Cleo and was informed of Selwyn and Eldon Tyrell's plan to give Cleo over to the Tyrell Corporation as payment for her replicant mother. Selwyn and Tyrell men arrived at El Santuario, prompting a gunfight. With Isobel staying to provide them with cover fire, Cleo was taken by Ash back to Los Angeles, deciding to look after her. Ash then asked Cleo of another safe place, to which Cleo pointed up in the air.