You want to know about one of the most heart breaking moments of Infinity War? Bucky dying, and seeing how completely and utterly broken Steve is watching his friend turn to ash right before his eyes and knowing this time thereās nothing he can do.
He lost Bucky the first time when he fell off the train, watching as his best friend fell hundreds of feet to his death. Maybe he could have saved him if heās been just a little faster. Reached a little farther.
He finds Bucky over seventy years later, but the man he once was has long since been replaced by Hydraās creation. This doesnāt stop Steve, though. Itās his chance to make up for losing Bucky the first time. He succeeds, but loses Bucky again when his former friend saves him frown drowning in a lake, and disappears into hiding.
Two year later, Steve finally gets Bucky back after finding him in Romania, only to lose him yet again when Bucky goes back into cryo.
You can see how happy Steve is when he walks over and pulls Bucky into a hug, having gone another two years without seeing him. He knows the world is basically ending, but somehow being with Bucky makes it seem like everything is going to be okay.
...until it isnāt, and Steve is forced to watch as he loses his friend for what looks like the last time. He sees Bucky turn to ash right before his eyes, realizing this is it. This is the time where Bucky doesnāt come back, and Steve is powerless to stop it. He collapses to the ground in disebelief, hands reaching out to where his best friendās ashes lay scattered over the ground. The team is talking to him, trying to ask their leader what the hell happened. All he can do is stare at the lost battle in shock.