Upon being alerted of the drowning of her son, Jason, during a boating accident with daughter Cheryl, Penelope and her husband Cliff Blossom joined the local authorities at Sweetwater River to retrieve Cheryl.
When Jason's body was eventually discovered, Cliff, Penelope and Cheryl arrived at the morgue to positively identify him. As the coroner revealed the body, Cheryl and her mother both turned away in horror, while Cliff mutely stared at the corpse of his son.
The night of Riverdale High School's annual fall Pep Rally, Penelope sat in the front row of the bleachers with her husband as Mayor McCoy dedicated the event to the memory of Jason and watched Cheryl perform with the River Vixens. Shortly after the performance Penelope became concerned as Cheryl raced off the stage crying, after she had seen Archie in Jason's football jersey enter onto the field.
When Sheriff Keller interrogated Cheryl about the lies she had told regarding her last encounter with her brother, Penelope and Cliff interrupted in a state of anger and abruptly ended the meeting. Penelope brusquely ordered her daughter not to say another word and rushed Cheryl out of the office. She queried why Cheryl didn't contact them, and told her she would be telling them everything when they returned home, to which Cheryl remained silent.
After having fallen asleep in her brother's bed, Cheryl woke from a nightmare to find her mother watching her from the doorway. Penelope told her there would be no more sleeping in Jason's bed. Cheryl explained that she dosed off while working on her eulogy, unfortunately, Penelope abruptly put an end to that, and told Cheryl that she would not be allowed to speak at the Jason's memorial, as she would only run the risk of embarrassing the family.
That evening, the Blossom family ate diner together and were joined by Veronica Lodge at Cheryl's invitation, yet Penelope remarked had no idea why she was there. Cheryl commented on the subject of her being prevented from speaking at Jason's memorial, which caused Penelope to remind her that she already said her goodbyes to Jason, when she rowed him over Sweetwater River, to his death. At the memorial the next morning, Penelope looked on angrily as Cheryl hijacked the service to speak to the guests about Jason. Furious with Cheryl over her disobedience, Penelope explained to her that, as punishment, she'd no longer be on the River Vixens, and if not for the fact that no one wanted Cheryl, she'd be shipped off to boarding school in Europe.
With the discovery of Jason's getaway vehicle on route 40, Penelope went down to the Sheriff's Station to inquire whether they had made any headway in Jason's case. Cheryl unexpectedly showed up and offered some new information, but only if Penelope allowed her back on the River Vixens, to which she exasperatedly agreed. Cheryl revealed that Polly Cooper had escaped the Sisters of Quiet Mercy group home the very same night the car had been set ablaze. She thought it was very likely that Polly was the culprit of both the fire and her brother's murder. Following the revelation, the Blossom's orchestrated a search party throughout Eversgreen Forest to locate Polly, however, witch hunt would appear to be the more accurate term, during which they ran into the Coopers who had organized a search of their own. With the search unsuccessful, Cheryl, Penelope and Cliff attended a press conference held by Alice Cooper, where they were shocked to learn that Polly was pregnant with Jason's child.
Through Cheryl, Penelope and Cliff arranged a meeting with Betty Cooper at Pop's Chock'lit Shoppe hoping to further discuss the plans for Polly and the baby and were relieved to learn that both were safe. Penelope told Betty they wanted to offer emotional support and Cliff assured Betty that money would never be a problem for them. Penelope asked where Polly was residing, but Betty refused to answer, so she reminded her that she and Polly were members of the Blossom family now, and they'd be ferociously protected, as long as they all trusted each other to which Cheryl looked uncomfortable. Back at Thornhill, Penelope asked Cheryl if she had ever seen Polly take drugs, which Cheryl wasn't sure. She then asked why and Penelope explained that she wouldn't want an unfit mother to raise her grandchild.
Surprisingly, even after she was accused of being an unfit mother, Polly invited Penelope and Cheryl to her baby shower, held at The Pembrooke by Betty and the Lodge's. Penelope began the event with an apology for embracing the child and not her, and hoped Polly could forgive her. During the gift portion of the shower, Penelope and Cheryl presented Polly with a miniature rocking horse, and explained it was a family heirloom that great-grandfather Blossom had played with. Cheryl then excitedly extended an invitation to Polly for her to stay with them at Thornhill, which Penelope assured her was genuine and that she and the child would want for nothing. Unsurprisingly, this didn't go over well with Alice, which led to an argument between the three. Polly screamed at them to stop and claimed their non-stop fighting is what led to Jason's death. The next morning, Penelope and Cliff welcomed Polly to their home as she had accepted their invitation to stay at Thornhill.