- "Hey, are you okay? Do you need a doctor?"
"No. I'm not sick, just scared."
"Everything's gonna be okay."
- —Supergirl and Adelaide[src]
In April 2018, Adelaide Swanson brought her specialty cookies for her coworkers at City Hall at a mobile flu unit.
The next day, Adelaide handed out her cookies all around City Hall. Just then, a mysterious disease began spreading, causing the mayor to order a quarantine on City Hall. Adelaide watched the chaos, terrified of the situation. Supergirl comforted Adelaide, assuring her that everything was going to be okay. After the quarantine was lifted, Adelaide went home.
Due being in contact with all the infected patients, Adelaide was initially suspected to be Pestilence, the source of the outbreak. That night, Supergirl, Saturn Girl, and the D.E.O. went to Adelaide's apartment, only to find that she was a victim of the plague and had died of organ failure.