Mr. Freeze returns, but this time, he is focused on destroying everyone's happiness. This is because his wife left him, believing that he died in the events of Batman & Mr. Freeze: Sub-Zero. It's up to Batman and Batgirl to stop his latest scheme: freezing all of Gotham.
- Big "OMG!": Batgirl says this upon seeing Freeze in a robotic spider body.
- Call-Back: Two to Heart of Ice.
- Mr. Freeze leaves one of his ice maidens behind after her ankle gets frozen, just like in his debut episode. Unlike the henchmen from that episode, the other ice maidens don't even try to help her, and neither does Batman.
- Freeze once again say he would be moved if he was still capable of doing so.
- Deadpan Snarker: After the doctors are released.Batgirl: [tries walking away] Well, I guess we're next.
Ice maiden: [stopping her] Cute.
- Despair Event Horizon: Mr. Freeze hits this so hard.
- Evil Is Petty / Revenge by Proxy: Mr. Freeze's M.O. in this episode. He goes around kicking dogs just because it would make the victims as miserable as he is.
- Foreshadowing: The captive doctors talking to Freeze about stabilizing his condition and how they did the best they could. Later, he tells Bruce that it's "much too late" for him to be helped now. Batman and Batgirl also find Freeze's empty suit lying around in the lair; they initially figure it's a spare because it's not cold enough there for Freeze to go without.
- Freudian Excuse: A news report shows Bruce making a sizable donation to an orphanage. He says his father taught him that those who have the most must give the most.
- Happy Ending Override: To Batman & Mr. Freeze: Sub-Zero where Nora was cured and Freeze resigned to live in quiet happiness in the Arctic with his polar bears. Except Freeze's condition has completely destroyed his body and his seperation from Nora has driven him insanely bitter from the rest of the world.
- Hope Crusher: "Search your heart for the thing you value most. Then despair, for I have come to take it from you."
- Hypocritical Humor: Failing a civics test, Tim says he thinks the American justice system is bogus. When Bruce asks how he came to that conclusion, Tim says by watching Batman in action. As Tim points out the lack of due process, Bruce tries to change subjects by asking how he did on a math test.
- Little "No": A woman when Freeze gets ready to shoot her dog.
- Never Found the Body: The episode ends with a closeup of Freeze's body suit, without Freeze's head in it. We see in Batman Beyond that he did survive. Much to his regret.
- Not So Stoic: Even Batman is stunned to see what's become of Mr. Freeze.
- Paid Harem: Freeze has an all-female gang of "ice maidens" in this episode, all just as cold (metaphorically) as he is.
- Parental Substitute: Mr. Freeze points out both sides of it for Bruce.Mr. Freeze: You were just a boy when you lost your family, but you keep trying to create a surrogate family for yourself. To destroy you, I need only destroy that. Perhaps your beloved surrogate son. [points his freeze ray at Tim] No. I think the surrogate father. [blasts Alfred]
- Plot Armor: Good thing Freeze's ice blast just happened to leave Alfred with his head sticking out.
- Training from Hell: Batgirl gets this one when Bruce increases her training difficulty level to 10, which leaves her getting almost shot by the lasers.
- Watching Troy Burn: Mr. Freeze's plan for revenge on Batman is to hold him captive as he is Forced to Watch Freeze destroy Gotham.
- Wham Shot: Freeze's head on robotic spider legs.
- Woobie, Destroyer of Worlds: This episode shows what happens when someone who could already be pretty dangerous goes even further."You understand now why I could not return to my Nora, my treasure. There's no hope for me, or you, or your city. Everyone's going to feel my loss!"
- You Have Failed Me: Mr. Freeze leaves one of his ice maidens behind after her ankle gets frozen.