Stark knew that in reality Steve didn't want to put pressure on him. After all, Stark was the first victim who was still alive in this matter.
Since Steve was willing to be considerate towards Stark, he too was willing to show him the same courtesy, opting for a more peaceful way to interrogate him rather than storming a mental hospital, taking Bucky by force, and then badgering him.
Bucky understood this, so without waiting for Stark to ask, he laid it all out:
"At that time, I received an order from a senior official in Hydra. I didn't know who issued the order because I was just a murderer - they wouldn't allow me to know too much."
"They ordered me to intercept the car of Mr. and Mrs. Stark and set off a car bomb. I laid a trap on the highway, and once the car stopped, I jumped onto the hood and shattered the windscreen with my fist."
"At that time, I heard Howard Stark exclaim 'Sergeant Barnes?!'"
"He recognized me, but couldn't stop what I did next because at that moment, I could only follow orders."
Bucky took a deep breath, his mechanical arm gradually tightening into a fist. He said, "My fist hit his chest, but that did not kill him. He pressed a button in the car, thinking that he was going to activate a weapon, so I blew up the car engine… "
"Everything ended in an explosion." Bucky's voice started to tremble: "After the flames were extinguished, I went up to ascertain whether the mission was completed. Indeed, it was the corpses of Mr. and Mrs. Stark."
"In addition, I found the remains of what seemed to be a confidential file safety box in the trunk, but due to the violent explosion, nothing was left."
After speaking, he opened his clenched fist, waiting for judgement as if resigned to his fate.
The next second, Iron Armor grabbed his neck, pinned him against the wall, the glimmer on Iron Man's mask reflected a mechanical indifference and ruthlessness.
In his struggle, just as Bucky was about to pass out from asphyxiation, Iron Man heard him squeeze out a single word from his throat: "...Thank you."
The next second, Iron Man loosened his arm, and Bucky fell to the ground, his head slumped to one side. The face mask opened, and Stark stared at Bucky, asking, "Why 'thank you'?"
Bucky seemed to finally break down, his mechanical arm rested against the wall, his fingertips digging into it, his voice trembling, "If you can kill me, I ought to thank you. You've served me my just desserts, henceforth, no more torment..."
"Ever since I regained my senses, all the scenes in my memory have been playing in my head non-stop - the pleas, cries and death of innocent people tormenting me incessantly…"
Bucky paused for a moment, then said: "But I know, I can't commit suicide, because I still have to support Steve, otherwise, he would be truly alone."
"He doesn't love this era at all, in fact, he always wishes that he hadn't awakened."
"Nothing in this era can sustain him to continue on, and I have to survive, to become like him, a testament of that era, reminding him that he is not alone, even if this means facing endless, ceaseless guilt and despair…"
"You should definitely kill me…" Bucky clenched his teeth and said: "Only you can kill me, only you can end all this…"
But at this moment, Stark actually calmed down. He peered down at Bucky who was seated on the ground and said, "But I won't do that, not just because I want you to be punished."
"If I killed you, Steve would face the same tragedy again. One friend killing another friend. As you've said, he cannot bear such a tragedy for the second time."
After saying that, Stark turned around, neglecting to look at Bucky, struggling to compose himself.
After a while, he turned back around and asked: "What was Howard's expression like, and his manner, before you killed him? Tell me every detail, and any clues you think are valuable…"
"I'm just a murderer, I don't know too much…" Bucky, still seated on the ground, curled a leg underneath himself, his head lowered, "It was the winter of 1991, close to Christmas, many staff from the base went home for the holiday…"
"An assistant scientist, wrote the new orders and brainwashing program into my brain, which included Stark's specific travel information."
"How did they obtain that information?" Stark asked, his brow furrowing.
Bucky shook his head and said, "I don't know, but the information was very detailed, down to which highway he would take at what time, and at what moment he would pass a certain road sign."
Stark's brows furrowed even deeper, Bucky continued, "They set the program, I appeared when I was supposed to, and when I jumped on the hood of the car, Howard didn't look surprised."
Stark widened his eyes, "...What did you say?!"
"I said, he didn't seem surprised about being attacked. The surprise later was because he recognized me, he recognized that I was 'Bucky Barnes.'"
Then, Bucky turned to look at his mechanical arm and said, "I'm not sure, but it seemed like, back then, Howard took a look at my arm… and seemed to show surprise and anger."
Stark's brow furrowed even deeper. He didn't realize that such details were hidden within that assassination. What was so special about Bucky's mechanical arm? Why did Howard stare at it moments before his death?
"When Howard discovered that someone was attacking his car, he subconsciously wanted to press a button. I punched him but it didn't stop his action; he had anticipated all of this…"
Stark took a deep breath and said, "How is that possible? Wasn't he ambushed unexpectedly? How is it possible that he knew he was going to be attacked and didn't dodge it?"
"Perhaps, he knew that this day would come." Bucky took a deep breath and said, "Hydra at that time wasn't as easy to deal with as you imagine now. Howard Stark had already become a thorn in their side. Maybe he expected that Hydra would kill him."
"Then why didn't he protect himself or seek asylum?" Stark said incredulously, "He knew someone wanted to kill him and he still didn't dodge??!!"
Bucky pursed his lips as if he wanted to say something but ultimately fell silent. Stark noticed this and stared at him, asking, "...What did you want to say?"
Bucky hesitated, but finally said: "He maybe didn't want to run, he just couldn't."
For the first time, Bucky looked straight into Stark's eyes and said, "In that era, every person charging over the front line had something behind them that made them unable to flee, unwilling to flee, and despite knowing death was inevitable, they still bravely dashed forward."
"It wasn't the era that shaped them; instead they built that Golden Age."