Synopsis
This series covers the first 2+ years of Timely history, leading up to the formation of the Invaders after Pearl Harbor. Its first 3 issues centre on the Human Torch and the Sub-Mariner, but they include a thread following the build-up to Project Super-Soldier which will create Captain America.
The series is narrated by Thomas Halloway, the Angel, in a journal that will surface in modern times in the last issue. It will include cameos by many other Timely heroes created in the first year. As such this series is a companion to the Marvel Mystery Handbook which describes the first year's crop of characters.
Angel was introduced in the first Timely comic Marvel Comics #1, which became Marvel Mystery Comics from #2, along with Human Torch and Sub-Mariner. He racked up the most 1940's appearances after the big 3 (HT, SM and CA), mainly in most issues of MMC and the 1940's Sub-Mariner Comics.
This issue opens in New York in 1938 where Dr Halloway is treating an old man Matt Hawk, who claims to have been to the future, and seen a world of super-heroes. When he dies he leaves Halloway a domino mask and two guns, revealing that he used to be the Two-Gun Kid. The story hints that Hawk knew the day he would die, and that Halloway will become the Angel. We get a glimpse of Halloway's upbringing, absorbing knowledge from books in the prison library, where his father was warden. For some reason he lives in an unused cell. This glimpse of Halloway's early life comes from Angel's origin text story in MMC#20.
We now skip forward to 1939 where we learn that the US government is funding the experiment of Prof Horton, whose creation unfortunately keeps catching fire when exposed to oxygen. They are concerned about a Nazi Project Nietzsche to develop superior humans, and detail Lt Sawyer to do something about it. They also wonder what the Germans are doing in the Sargasso Sea. In fact they are killing Atlanteans with depth charges and sending their bodies to Project Nietzsche for study. Until the Sub-Mariner stops them. Namor's appearance here is non-canonical. It provides a more immediate reason for his subsequent attacks on mankind. And explains why he eventually sides with the US against Germany.
The government tells Horton to display his combustible synthetic man, the Human Torch, in order to worry the Germans. The government's involvement with HT's creation is invented here. Horton's partner Dr James Bradley quits in disgust. Dr Bradley is a Roy Thomas addition, from the Invaders v2 limited series. He takes another android body with him when he leaves, and they reappear as villains Dr Death and Volton in the Invaders story. There are several characters like this inserted quietly into this series. (But I can't find any other reference to Erskine's co-worker Hans Bruder, nor Rascher who is experimenting with freezing people.) After the unveiling, due to public fear, Horton is ordered to bury the Torch for safety.
News of the Torch reaches Project Nietzsche, where Prof Erskine is sickened by their experiments and sends a message to England asking to defect. Prof Abraham Erskine is of course the scientist who will turn Steve Rogers into Captain America. In London Lt Sawyer recruits Nick Fury and Red Hargrove to extract Erskine. They have been training British paratroopers. Lt Sawyer will be the c/o of Sgt Fury's Howling Commandos. Fury and Hargrove were pals since boyhood as seen in SFHC#7 and #34.
Halloway watches a newsreel of Nazi conquests in Europe sitting next to Steve Rogers, as a repeat of the scene in #4 confirms. The #4 version also suggests they are watching the invasion of Poland. Horton has been educating Torch inside his prison by wireless. A leak lets Torch flame on and escape. Halloway helps with the resulting devastation. And decides to put on Two-Gun Kid's mask.