Upon being alerted of the death of her son, Jason, while out boating with his sister Cheryl, Penelope and her husband, Cliff, joined the local authorities at the edge of Sweetwater River, however, despite dragging the river, they could not find Jason's body. Eventually, Jason's corpse washed up on the shores of Sweetwater and Penelope and Cliff were forced to stand aside as their son's body was taken to an ambulance in a body bag by the authorities. As they passed, Penelope reached out to her son.
Penelope, Cliff and Cheryl were brought down to the morgue in order to identify Jason's body. As the cloth was pull off his head, both Penelope turned away, horrified.
Despite their recent tragedy, Penelope and Cliff attended the first annual Taste of Riverdale event, during which, Penelope had a brief, but violent run-in with Alice Cooper. Penelope was appalled that Alice had dared to print her son's autopsy results in her newspaper, The Register, and slapped her on sight. Distraught over what had happened to her son, she was pulled away by her husband in tears.
In the days leading up to their son's memorial service, Penelope and Cliff composed a list of people they suspected could have killed their son and informed Sheriff Keller that they had all been invited to the funeral. Penelope believed there was a strong possibility that Jason's killer would soon be in their home.The day of the memorial, Penelope stood by the door, greeting guests as they entered and met with Hermione Lodge who she coldly accused of taking pleasure in Jason's death, bringing the regards of her husband, Hiram Lodge. Later, as the service was set to begin, Penelope was approached by Archie Andrews, who offered her Jason's jersey from his time on the Riverdale Bulldogs. She couldn't help but notice the similarities between Archie and Jason and caressed his face before catching herself and accepting the jersey. After the service, Jason was laid to rest in the cemetery on Thornhill's grounds and upon his grave Penelope placed white flowers.
While at the Sheriff Station to inquire about her son's case, Penelope learned from Cheryl that Polly Cooper had escaped from the Sisters of Quiet Mercy group home the very same night that Jason's getaway car was set afire. Suspecting her to be the killer, the Blossoms organized a search of Eversgreen Forest to find her, during which they ran into the Coopers, who had a search party of their own. Penelope angrily informed Alice that she was certain Polly had killed her son and soon the entire town would know too. However, Penelope later attended a press conference held by Alice Cooper where she was shocked to learn that Polly was pregnant with Jason's child.
Once Polly had been found, the Blossom's met with Betty at Pop's Chock'lit Shoppe to discuss the baby. Penelope informed her they would offer emotional support, as well as financial, though, later, she questioned Cheryl about Polly and explained that she wouldn't want an unfit mother to raise her grandchild.
While looking through Penelope's jewelry, Polly and Cheryl discovered the heirloom engagement ring that Jason had used to propose to Polly with. As they had believed it had burned when Jason's getaway vehicle had been set ablaze, they were suspicious as to how it got there. Later, Penelope revealed that Clifford had spoken to Jason shortly before his death, and he had told his father that he wanted nothing more to do with the name or lineage of their family, including the ring, which he threw in Cliff's face as a final rebuke. Cliff then gave the ring to his wife for safekeeping.
Following the arrest of FP Jones for Jason's murder, Penelope wept angrily and told her husband that she wanted FP dead for what he had done to Jason. Unbeknownst to either that Cheryl was watching, Cliff held Penelope as she cried and promised to take care of him.