Justice League Action: Season 1, Episode 20

1 - 20: Freezer Burn

"Freezer Burn" Mr. Freeze flies on his freeze gun-wielding airship to freeze all of Gotham City using Killer Frost as his power source after tricking her into an alliance after she evaded Firestorm. While Batman deals with Mr. Freeze, Firestorm will have to save Killer Frost where he develops a crush on her at the same time