Killer Frost participated in a super villain breakout at Belle Reve Penitentiary. Together with other ice based villains, she was supposed to weaken the walls of the Penitentiary, while super strong villains would smash the weakened walls down. She discovered that Miss Martian was disguised as Tuppence Terror when she used her telekinetic abilities to stop Killer Frost from killing the guard and froze her in an ice pillar. When Superboy and Icicle Jr. broke through the wall into the female wing, Superboy subdued the female villains quickly after seeing M'gann's state. Killer Frost remained in custody in Belle Reve.
After five mysterious ice fortresses covered the United States with a blanket of snow, Batman and Flash suspected Killer Frost and the other ice-villains were involved. Hugo Strange told them they had been, and still were, in their cells.However, Killer Frost was in fact responsible for powering one of the fortresses.
Killer Frost was sent to Siberia with Sportsmaster and Icicle Jr. to protect the excavation of a Babylonian artifact. Killer Frost also ran a side operation that involved freezing local villagers. Superboy and Alpha Squad defeated her before moving on to the other two villains.
Killer Frost was mind-controlled into fighting against Infinity, Inc.. The whole fight was orchestrated by Lex Luthor to boost his metahuman team's popularity. Killer Frost was easily defeated and taken away by the authorities.
There are three versions of Killer Frost in the comics, all villains of Firestorm (Ronnie Raymond/Martin Stein). The first (Crystal Frost), gained her powers after accidentally locking herself in a thermafrost chamber, driving her insane in the process. Frost became the archenemy of the hero Firestorm, allying herself with the Secret Society of Supervillains before dying in battle with Firestorm. Her successor was Louise Lincoln, a friend of Frost's who repeated her incident out of respect to her mentor. Louise gained her predecessor's powers and insanity, again facing off against Firestorm in revenge for Crystal's death. The third, Dr. Caitlin Snow, was a scientist from S.T.A.R. Labs who was involved in an accident.
This is Killer Frost's 4th animated appearance. She was featured in the DCAU series Justice League and Justice League Unlimited, Batman: The Brave and the Bold, and Superman/Batman: Public Enemies.