The father-daughter relationship between Hal and Polly Cooper was estranged due to Polly being pregnant with Jason Blossom's baby, who was the son of a family Hal despises. Their relationship is also estranged as Hal wanted Polly to abort her baby, but Polly chose to keep them. Due to Polly's pregnancy, Hal refused for Polly to come live back with them because he refuses to have as he puts it "Blossom blood in his household". However, after Hal reveals that the real reason he hates Polly's pregnancy is because she and Jason were blood relatives, Hal becomes more open to Polly and allows her to come with the family. Although Polly hasn't forgiven him and left home again shortly afterwards not allowing him to meet his grandchildren.
Presumably, father and daughter had a good relationship before Polly began dating Jason Blossom. When Hal found out about the two he was furious and he and wife, Alice, tried to break them up. They were thrilled when Jason's parents forced him to do so, despite their daughter's heartbreak.
After learning of Polly's pregnancy, Hal and Alice conspired to send her away to a group home so no one would find out, however, Hal went behind his wife's back and made a appointment for Polly to receive an abortion, never asking whether or not that was what his daughter wanted, damaging their relationship.
To cover up Polly's pregnancy, Hal and Alice told everyone, including younger daughter Betty, that Polly had a nervous breakdown when Jason broke up with her, and that was why she was sent to live at a group home.
After reading their published article of the Black Hood's letter in the Register, Polly told her father and mother that she had decided that she would be leaving Riverdale for her own safety. She had already made arrangements at the Farm. What Farm, Alice wondered. Polly explained that she was referring to the very same Farm that she and Jason had planned to run off to before he was murdered. Hal suggested that Polly settle down, so that they can talk about what to do next. Polly was worried about her well being, as well as the well being of her unborn babies. With the killer targeting sinners, she was no longer safe in Riverdale considering that she was an unwed mother carrying her cousin's babies. Over Alice's dead body would she allow Polly to run off and give birth at a Farm, though she didn't have much say in the matter as Polly had already made up her mind. She stormed off, with Hal not far behind, hoping to talk some sense into her.
Polly, Hal and Alice appeared in Betty's anxiety induced nightmare. Polly entered Betty's bedroom to wake her up from her sleep and tell her that Santa Claus was downstairs. Polly then joined their parents by the fireplace as Betty came down the steps. Moments later, Polly, Hal, and Alice were all dead. They had been murdered by the Black Hood who had disguised himself as Santa.
- ↑ Maxwell, Ross (writer) & Warn, Jesse (director) (February 23, 2017). "Chapter Five: Heart of Darkness". Riverdale. Season 1. Episode 5. The CW.
- ↑ Williams, Tessa Leigh & Zwart, Nicholas (writers) & Adelson, Steve A. (director) (March 2, 2017). "Chapter Six: Faster, Pussycats! Kill! Kill!". Riverdale. Season 1. Episode 6. The CW.
- ↑ Allen, Aaron (writer) & Anders, Allison (director) (March 9, 2017). "Chapter Seven: In a Lonely Place". Riverdale. Season 1. Episode 7. The CW.
- ↑ Cohen, Julia (writer) & Katzenberg, David (director) (March 30, 2017). "Chapter Eight: The Outsiders". Riverdale. Season 1. Episode 8. The CW.
- ↑ Maxwell, Ross (writer) & Sullivan, Kevin (director) (October 25, 2017). "Chapter Sixteen: The Watcher in the Woods". Riverdale. Season 2. Episode 3. The CW.
- ↑ Boucher, Shepard (writer) & Seidenglanz, Rob (director) (December 13, 2017). "Chapter Twenty-Two: Silent Night, Deadly Night". Riverdale. Season 2. Episode 9. The CW.