Writer:	Paul Dini
Director:	Bruce Timm
Star:	Efrem Zimbalist Jr. (Alfred Pennyworth),  Kevin Conroy (Bruce Wayne / Batman)
Recurring Role:	Mari Devon (Summer Gleeson)
Guest Star:	John Mariano (Additional Voices),  Robert David Hall (Additional Voices),  Michael Bell (Additional Voices),  Michael Ansara (Victor Fries / Mr. Freeze),  Mark Hamill (Ferris Boyle)

This episode marks the first appearance of Ferris Boyle; Summer Gleeson; Nora Fries (in frozen isolation) and Dr. Victor Fries/Mr. Freeze (edit) This episode along with "The Cat And The Claw, Part 1 and 2" and "See No Evil" was released on DVD as Batman The Animated Series: Secrets Of The Caped Crusader. (edit) The Toon Disney airing of this episode has Freeze saying ""To never again walk upon a summer's day with a hot wind in your face and a warm hand to hold. Oh, yes", removing the part where he says "I'd kill for that." Also cut was Batman saying "My God" after watching the incriminating video of Mr. Freeze's "birth". (edit) In 2005, Wizard Magazine selected "Heart of Ice" as the best episode of the BTAS. (edit) Paul Dini's favorite episode of the series. (edit)

Mr. Freeze: I failed you. I wish there were another way for me to say it. I cannot. I can only beg your forgiveness and pray you hear me somehow... someplace. Someplace where a warm hand waits for mine. (edit) Mr. Freeze: Sooner or later all who stand in my way must feel the icy touch of death! (edit) Ferris Boyle: (being frozen) Stop... Please... I beg you!
Mr. Freeze: You beg? In my nightmares I see my Nora behind the glass begging to me with frozen eyes. How I've longed to see that look frozen on you! (edit) Mr. Freeze: The cold eyes of vengeance are upon you, Boyle. (edit) Mr. Freeze: Let the evil that walks inside be cleansed by pure unforgiving ice. (edit)

Toon Disney does a rather interesting edit to this quote...

Mr. Freeze: Think of it Batman. To never again walk upon a summer's day with a hot wind in your face and a warm hand to hold. Oh yes, I'd kill for that.

Toon Disney cuts out "I'd kill for that" making it not nearly as emotional. (edit) Goof

Two times the colors of the bat logo on Batman's chest switches, yellow bat on a black oval.
The first time just after Batman breaks his 'ice-cuffs', while hanging upside down.
The second time when he lands after knocking out the guy behind the control panel of the freeze canon. (edit) Batman's uttering "My god!" was quite unusual for a network cartoon at the time. (1992) Normally, the censors wouldn't have passed words directly discussing religion, like god and hell. In particular, using "My god!" in that context would have been considered blasphemous by most cartoon censors. Taking God's name in vain was as equally frowned upon as even positively discussing religion in cartoons. (edit) The tape of the accident that created Mr. Freeze features close-ups and jump cuts. If the recording was automated as it appears to be, this is not possible. (edit) When Batman is dressed as a security guard he reaches into his Batbelt and pulls out the key card. As he reaches for the card, it appears in his hand out of nowhere. (edit)

Star Trek

Mr. Freeze: Revenge is a dish best served cold.

This quote is most remembered as line spoken by the title villian in the movie Star Trek II: The Wrath of Kahn. The line is a dual allusion; in the movie, Kahn mention the saying is a Klingon proverb. Michael Ansara, who voices Freeze, played the Klingon captain Kang in several Star Trek episodes, starting with TOS episode "Day of the Dove". (edit) Tim Burton's Batman Returns

When Batman is trying to stop the freezing of Ferris Boyle's building, he is attacked by a thug from behind. He dispatches the thug with a quick back elbow which is very similar to a scene in Batman Returns (1992). (edit)