Warning: The following contains SPOILERS for Harley Quinn Season 2, Episode 4, "Thawning Hearts."

DC Universe's Harley Quinn season 2, episode 4, "Thawing Hearts," made reference to a failed attempt to change Mr. Freeze's origins as part of the critically reviled New 52 reboot. At the same time, the episode affirmed Mr. Freeze's relationship with his beloved wife, Nora Fries, and his turning to supervillainy in a bid to save her life.

When he was originally introduced into the Batman comics in 1959, Mr. Freeze was just another bank robber with a freeze ray. He was given a new lease on life in the Batman: The Animated Series episode "Heart Of Ice," which gave Dr. Victor Fries a tragic backstory as a scientist who misappropriated his employer's cryogenics equipment to preserve his wife while he researched a cure for the rare blood disease that threatened to kill her. When Victor's unsympathetic boss learned what he was doing and ordered the tank holding Nora to be unplugged, a fight broke out which ended in an accident that left Victor unable to survive outside of sub-zero temperatures. The new background proved so popular that it was brought into the DC Comics' Universe and used as part of the plot of Batman and Robin.

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Mr. Freeze was given a new backstory in Batman Annual #1, shortly after DC Comics rebooted their reality through the 2011 storyline Flashpoint. The new history painted Dr. Victor Fries as a lonely man who became obsessed with a cryogenically frozen woman named Nora, while working for the cryonics research department of Wayne Enterprises. This time Bruce Wayne was cast in the role of the unsympathetic employer who started the fight that ended in Victor Fries' accident and the delusional Mr. Freeze insisting that Nora was his wife. While Scott Snyder's run on Batman was largely loved by fans and critics alike, most agreed that his new take on Mr. Freeze was one of the worst retcons in Batman history. The loving relationship between Victor and Nora was quietly restored by later stories.

Harley Quinn Nora Fries and Victor Fries Mr. Freeze

"Thawing Hearts" seems to make reference to this failed reboot through how Harley comes to believe that Nora Fries is the victim of a crazed stalker rather than a rare blood disease. The episode sees Harley and her gang taken hostage after they break into Mr. Freeze's hideout with the intention of killing him, though Victor is eventually persuaded to let them live while Poison Ivy puts her medical expertise to the test to search for the cure for Nora's condition. While they are waiting, Mr. Freeze fixes everyone lunch and tries to be a genial host, telling the story of how he and Nora met. Between their "meet-cute" story sounding like a half-hearted rip-off of You've Got Mail  and Nora's being frozen with a look of pure terror on her face, Harley concludes that Mr. Freeze is making the whole thing up and must be holding Nora against her will.

It spoils little to reveal that Harley Quinn is proven to be quite wrong and that her efforts to emancipate Nora only increase the urgency to find a cure for her condition. The ending of "Thawing Hearts" is guaranteed to warm even the coldest of souls, and any doubt that Nora truly loves Victor Fries and that he truly is a dedicated scientist trying to save the woman he loves is eliminated by the episode's end.

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