While Alice was off at a women and journalism spa retreat, Hal was approached by Betty who wanted to talk about Polly. Hal explained that Polly and Jason had had a fight, he was unsure what the fight was about, but Polly was devastated afterward. He claimed to have come home from work one day and heard the water running in the bathroom, so he knocked on the door, asking Polly if she was okay, but she didn't reply. Hal then kicked the door down to find Polly attempting to commit suicide, the reason she was sent away. After his heartbreaking talk with Betty, Hal proceeded to watch old home movies of Polly that night, while drinking his sorrows away.
After attending Jason Blossom's Memorial, where Betty learned from Rose Blossom that Polly and Jason were engaged, Betty confronted her father with the news, however, Hal was already aware of the engagement. She wondered if that was what she had seen Hal arguing about with Cliff Blossom earlier at the service. Hal explained that the Blossom clan came extremely close to destroying his family once upon a time. Cheryl's great-grandfather murdered his grandfather over money. They were business partners in selling and trading maple, but one day, Cheryl's great-grandfather decided that he no longer wanted to share the profits, so he killed Hal's grandfather. The Blossoms stole their livelihood, and Hal would die before he'd allow them to steal his daughter too. Angry, Hal told Polly that Jason had made Polly sick, so she would not be returning home until she was no longer sick and warned Betty to stay out of it.
After Betty and Jughead visited Polly at the Sisters of Quiet Mercy and learned of Polly's pregnancy, Hal became the target of Betty's suspicions as to who had killed Jason Blossom. He hated the Blossom family for stealing the Cooper family legacy, as well as Polly being pregnant with Jason's child, which gave Hal a great motive. Hal did not attend closing night for the Twilight Drive-In, nor was he with Alice, which led Betty to believe that he was not only the culprit that broke into Sheriff Keller's house, and stole all the case files on Jason's murder, but that he might have been the person who killed him, revenge for what Jason did to Polly. Hal and Alice accused Betty of sounding just as crazy as her sister, who Hal claimed was depressed and delusional, and her story about running off with Jason, just a fantasy. That night, Polly broke the window in her room and escaped the group home.
Determined to find Polly before the Blossoms could, Betty and Jughead Jones organized a search of Eversgreen Forest and instructed a group of volunteers, including Hal and Alice, to scour the woods between the Sisters of Quiet Mercy and the closest bus station, but the search was interrupted by the Blossoms. Afterward, Alice went into damage control mode and addressed the press outside a church that all the rumors about Polly were not true, and announced the one thing that she and Hal wanted to keep secret — Polly was pregnant with Jason Blossom's unborn child.
The next morning, Hal and Alice were asked a number of questions by Betty, such as if Polly and the baby would be staying with them at the house. Hal and Alice lied to Betty, they told her that Polly decided to give the child up for adoption. Hal firmly stated that was Polly's only option. However, Betty was already aware that that was not true, as she had secretly found Polly the night before, hidden in the attic of their home, and knew her sister wanted to keep her baby.
Following Polly's baby shower, which Hal did not attend, Hal was confronted by Alice, who demanded to know what he said to Polly after the discovery of her pregnancy. According to Polly, Hal had made an appointment with a doctor to get rid of Polly's 'mistake', meaning her pregnancy with Jason child. He did this, all the while keeping it from Alice. He claimed Polly wasn't ready for a child and sending her to the Sisters of Quiet Mercy wasn't enough because the child belonged to the Blossoms, and he refused to be party to raising a child that had Blossom blood. As tears filled her eyes, and her anger consumed her, Alice shoved Hal yet again, yelling at him to get out the house before she did something they'd both regret.