Appearing in "The Shadows of the Past"
- Captain America (William Burnside)
- Bucky (Jack Monroe)
- Communists (Only appearance)
- Scarecrow (Ebenezer Laughton)
- Mister Buda / The Contemplator
- Adam II (Only appearance; dies)
- Invaders (Only appearance)
- Third Reich (Referenced)
- Adolf Hitler (Mentioned)
- Emperor Hiroito (Mentioned)
- Liberty Legion (Referenced)
- President Truman (Referenced)
- Bucky Barnes (Referenced) (Deceased)
- Avengers (Referenced)
- Anthony (Scarecrow's henchman) (Only appearance)
- Elders of the Universe (Recap)
- The Devil (Invoked)
- Adam II (Recap)
- Golden Girl (Betty Ross) (Mentioned)
- George Washington (Mentioned)
- United American Undeground (Only appearance)
Races and Species:
- Pacific Ocean (1945 A.D.)
- Atlantis (Referenced)
- England, United Kingdom, Europe (Referenced)
- United States of America
- Heaven (Invoked)
- Hell (Invoked)
- Earth-8206 (Only appearance)
Synopsis for "The Shadows of the Past"
A cancer sticken Jeff Mace has had an conversation with the Contemplator, an Elder of the Universe. The Contemplator has agreed to pull the four Captain America's from their timeline and battle Adam II in an alternate universe where his robot hordes overthrew the world shortly after World War II. This will allow Mace to re-establish himself as the active Captain America or if he is unsuccessful to at least go out in a blaze of glory.
The Contemplator sends both Rogers and a now 20-ish Mace to the alternate Earth to fulfill Mace's desires. Mace is horrified to see the cost of his own selfish desires in the deceased and robotic converted counterparts of his friends in the former Invaders.
In the end, Adam II's regime is overthrown by Mace sacrificing his chance to defeat Adam II himself in favor of Rogers. Mace accepts that his time as Cap is over and accepts that Rogers is best suited to continue on as the active Captain America. Rogers accepts Mace's decision and helps Mace destroy Adam II which Mace does by crushing his own shield through Adam II's chest.
Mace and Rogers return to 1982 with Mace returned to his true older 60-ish age. Mace states that he is at peace with himself and accepts that his costumed adventuring is now finished and is now focused on confronting his cancer. Rogers accepts Mace as a good successor to the legacy of Captain America and wishes Mace good luck in his battle as Mace walks off to regular life.
- This issue estabilish as canon What If? #4, where it was originally explained that, after Steve Rogers and Bucky Barnes' apparent deaths, other men took the title of Captain America and Bucky, such as The Spirit of '76, The Patriot and Fred Davis (as Bucky).
- Captain America #155 already estabilished as canonical the 1950 adventures of Captain America and Bucky showed in Young Men #24 (and following issues), Men's Adventures #27 and #28, and Captain America #76–78: those Captain America and Bucky were retconned into being two different men, William Burnside (Captain America) and Jack Monroe (Bucky); also, Burnside legally changed his name into Steven Rogers.
- According to What If? #4, the Invaders, after the apparent death of Captain America and Bucky, renamed theirselves the All-Winners Squad; their adventures can be seen in All Winners Comics #19 and All Winners Comics #21 and in the special issue All Winners Comics 70th Anniversary Special #1; this issue named several times the All-Winners Squad as the Invaders.
- Both Nasland and Burnside are killed in this issue; they were later resurrected and returned to their proper place and time without knowledge of this events in this adventure.
- While all four Captain Americas are in this story at no time do all four Caps interact actively. Mace and Rogers only see Nasland and the 1950s Cap in suspended animation but do not interact with Nasland or the 1950s Cap at any time in the story. Nasland and the 1950s Cap basically parallel the story of Mace and Rogers where the 1950s Cap refuses to accept the wisdom of his own Cap counterpart Nasland who tries to get the 1950s Cap to go beyond his own self interest same as Rogers does with Mace. Though Mace finally does accept Rogers I's advice unlike the 1950s Cap which causes both Nasland and the 1950s Cap to be killed and converted.