The Iron Giant is about a young boy and his friendship with a towering metal robot from space.

Their story is both heartwarming and heartbreaking.

And so is the backstory to this animated classic as told in the behind-the-scenes documentary A Giant’s Dream, one of many extras on the recent Blu-ray debut of The Iron Giant.

The Iron Giant began as The Iron Man, a 1968 story written by English Poet Laureate Ted Hughes for his children after the suicide of their mother, writer Sylvia Plath, in 1963.

The Iron Man could disassemble into autonomous metal pieces and then reassemble — hence the father’s loving message to his grieving children: They could pick up the pieces of their lives, put themselves together again, and continue forward.

Decades later a young filmmaker named Brad Bird struggled with a similar unexpected loss: the murder of his sister, Susan, who was shot and killed by her husband.

After joining Warner Bros.’ Feature Animation Department and looking for a project to develop, Bird was drawn to The Iron Man.

“Maybe because I was still trying to draw together my own pieces after the death of my sister,” he said in the documentary, “I had an epiphany: What if a thing developed a soul and what if that thing found out that it was designed to kill, but didn’t want to kill? What if a gun had a soul and didn’t want to be a gun?”

Warner Bros. was interested in making The Iron Man into an animated-feature musical, based on the Who’s Pete Townsend’s 1989 musical adaptation, but studio executives listened to Bird’s “different take” on the story that was set in 1957 during Cold War paranoia about the Soviets, and featured a single mom and her lonely son, a government agent and a beatnik, and a child-like robot that discovers it has the powers to kill.

“At the end of [my pitch] they were like, ‘Damn. Yeah, let’s do this.’ And I loved the fact they were into it.”

It wasn’t the last good news Bird would hear from the studio, though it probably seemed that way.

Warner Bros. limited the director to a third of the budget and half of the production schedule for what was typical for an animated feature in the latter 1990s.

“Disney had five years,” Bird said. “We had two and a half.”

Bird and the animation team made their deadlines, only to watch Warner Bros. ignore and then bungle The Iron Giant’s marketing — something that was hugely important to a non-Disney/Pixar animated film in 1999. Thus small audiences turned out for the film’s opening weekend, despite its universal acclaim as an “instant classic.”

“It was like coming back to your house and finding it burned to the ground ... or your parents dying,” said The Iron Giant storyboard artist Mark Andrews on the documentary. “That’s how depressed we were.”

Bird’s directorial debut earned only $5.7 million its opening weekend in that early August and $23 million total — less than one-third of its $70-million budget.

The Iron Giant would later lead Bird to Pixar, where the writer-director created other animated classics like The Incredibles and Ratatouille, but at the time of its release he was “fretting because this labor of love is just tanking.”

And then Mexican filmmaker Guillermo del Toro, who was having his own box-office struggles in Hollywood, called him to offer his reassurances.

“What I said to him is ‘Look, in the light of the box office, the audience, the numbers, you feel like a loser, but this will pass,’” del Toro recalled in the documentary. “You have made a classic. It will stay in the hearts and minds of anyone that sees it. It will honestly live forever.”

After being rediscovered years later on DVD and now, hopefully, with this beautiful Blu-ray Signature Edition, The Iron Giant has the happy ending it’s always deserved.

Contact Kirk Baird at kbaird@theblade.com or 419-724-6734.

First Published October 7, 2016, 4:00 a.m.