Fran was one of the employees who hid inside the employee tunnels during the initial attack of the Great War. While being here, she and her boyfriend Evan slowly turned into ghouls.
When their hair started falling out and their skins rotting away, they had a huge fight. When the group at Kiddie Kingdom was attacked, Fran turned on the mist sprayers, spraying irradiated water in the air, which effectively ended the attack. She and her boyfriend eventually made up after this event.
After most on the group had died or turned into feral ghouls due to radiation, her sanity remained. Eventually she was locked up in a house by Oswald and Dean because she lost her sanity too.