Celestine was born to Ophelia and Mac Harkness. Not long after the kids were born, her father left them high and dry and Ophelia was forced to raise the children on her own. As the family grew older, Celestine had a family and became a nurse and Anna Mae moved away and got married to a man named Sam Keating and became a respectable lawyer in Philadelphia. As Ophelia got older, she needed more and more help with everyday tasks so Celestine felt responsible for making sure that she was taken care off ("Anna Mae")
Annalise Keating, her sister returns home. Not long after her mother tells the entire family and invites them all over to a party later on in the day. In the morning, Celestine goes to her room and lies in bed next to her until she wakes up. They both talk and she reveals that their mother will be hosting a party for her. Ophelia arrives and orders Annalise to go for a shower to get clean for her guests. Celestine tells Annalise that only a few people will come but then tells her that she is joking, that her mother has invited everyone. Downstairs, Annnalise, and Celestine discuss their mother's romance with her father, but are interrupted when Ophelia announces Nate's arrival. Annalise and Nate talk outside the house, while Celestine and Ophelia watch from the inside, commenting on Nate's physique. Despite Annalize's objections, Ophelia invites Nate to dinner. At dinner, Ophelia tells Nate that none of her children have had grandchildren, and Annalise's father tells her that it is because her daughters are women with careers and her son has not found the right woman, but raising children is a hard work. Annalise mocks because her father never tried, and to reduce tension Celestine invites everyone to dance in the room. The next day Annalise leaves. Outside of the house when they are saying goodbye Ophelia reminds Annalise that if he does not visit her more often he probably will not find her alive next time. ("Anna Mae")
Around a year later, her mother was diagnosed with dementia. Annalise came to visit her mother, Ophelia. Ophelia, her two daughters, and Mac sat down at the table to talk. Annalise and Celestine have been taking and Annalise said she wanted to use her insurance money from the fire to put her mom in a nursing home, but her mother was furious with the idea. During the night, Ophelia had a dementia episode, after which she agreed to visit the facility. Annalise’s father wanted to care for her herself, and they fought over who was to blame for her mom’s condition. Celestine assured her that it wasn’t her fault, and she confessed that the expected insurance payout wasn’t coming through. She further admitted she may be disbarred for her alcohol issues. “I’d be drinking, too, if I had your life,” her sister admitted. Annalise asked her mom point-blank what she wants to do, and the matriarch replied, “I’m going away. You know it, I know it. My mind’s going.” Noting her daughter’s past losses, she said she wanted to “protect you from losing any more.” But since dementia can’t be stopped, she said they need to “prepare,” prompting Annalise to break down. “Don’t worry, I’ll stay as long as I can,” her mother said. Not long after, Annalise left for Philadelphia. ("I'm Going Away")