WARNING: The following contains spoilers for Captain America: The End #1, by writer and artist Erik Larsen, available now
The threats Captain America deals with on a daily basis range from the freaky world of sci-fi robots and death rays to terrifyingly realistic concerns and social issues like drug abuse. But in Captain America: The End, Cap squares off against both rolled into one: a super virus that infects people with racism. It's up to Cap to discover the cure, but the odds are stacked against him.
The story is part of Marvel's The End titles, one-shots that take place in an alternate future that imagine an "ending" for heroes who are too popular to actually discontinue. Many of the stories in the series focus on heroic deaths or sacrifices by their heroes, but Captain America: The End returns to Cap's roots by having one last classic adventure serve as his send off.
The tale starts off in a dystopian world where the Red Skull has infected the world's population with a virus that gives them all the same gaunt, crimson appearance as the villain himself. Under the thrall of a hive mind controlled by a Skull-itized M.O.D.O.K., the world's population finds itself helplessly drawn toward violence against anyone different from themselves. Cap fights his way through hordes of the bigoted masses in an effort to find survivors -- and luckily he does.
Several survivors managed to stay free from the infection by holing up in a bunker, but shortly after Cap's arrival, the infection starts to spread to them too. In an effort to save one of the survivors, Cap transfuses his blood into her veins and explains that he is a universal donor. The moment is a set up for an important payoff later on: when Cap's only available weapon against the infected masses is a piece of shrapnel in his leg, he pulls it out and stabs his attacker with it. The transfer of his blood is a revelation -- Cap's blood is the cure to the Red Skull's virus!
Rather than sacrifice himself as so often happens to the heroes in the climax of The End comics, Cap manages to save the day by not sacrificing himself. Since his blood is the only cure, his death would mean the end of hope for curing the world of its infection. The comic quietly closes with Cap donating as much blood as possible, and stands as a testament to the idea that the best way to help the world isn't always sacrificing your life. Sometimes staying alive is the most heroic thing to do.