So yeah, it's no surprise that this this issue is largely a pastiche of Doc Savage, given its focus on Axel Brass. But at the same time, it's all about Elijah Snow as well. Beginning on the first page, we learn that Snow has no scent, and his temperature is different from other humans. At the same time, we learn that Doc Brass has a heightened sense of smell.
Moving on, the title page is another reference back to pulp novels. "The Good Doctor" is billed as a Planetary Novel, like "Strange Harbours" was a complete comic story in Planetary magazine. These flourishes, along with A Tale of the Planetary will be recurring motifs in the comic to come. But as I've noted, this issue is as much about Elijah Snow as it is Axel Brass, so this title page is a little bit of deception.
While there's been one or two references back to prior issues (notably the reference to Hong Kong and Brass' cameo in issue 4), this is a continuity-heavy story, with references back to Stormwatch, The Authority and the Daemonites for general Wildstorm references. As an aside, this story takes place sometime after the first Authority story arc but before issue 12 of that series.
For internal continuity, there's a lot going on here, mostly tying back into issue 1, but a lot of what's established here will inform later events in the story. Notably, it's the second issue in a row to mention the Hark Corporation, and here the link to Hark from Brass' team is made clear, as is the identity of his daughter Anna as the diving force behind it, but also that she has an agenda that requires subterfuge and patience - apparently to the point that she still hasn't acted at least 60 years later.
Brass and Snow's conversation has two themes running through it - melancholoy and suspicion. The melancholia is mostly on Brass' part. He was 45 when he fought the ersatz JLA to keep the world safe, and he's 99 now. He spent half his life in that cave, grievously wounded, and so we're given copious flashbacks to the first half of his life to hammer that sacrifice home. That sense of loss is amplified for those of us who are Wildstorm fans, with the references back to The High's attempt to change the world.
The suspicion then is Snow's part of the discussion. This is our first deep look at his personality - if Jenny Sparks is Earth's defence mechanism, Elijah Snow is its detective. He's working with Planetary but he doesn't trust the organisation - he's isolated from their motives and goals, and he's thinking about this right after an investigation involving the legacy of one of Brass' allies. He's motivated out of a desire to do good, showing regret that the world isn't the best it could be, citing Kaizen Gamorra's attacks in that first Authority arc as an example. But as Brass notes, Gamorra was stopped - by another Century Baby as it turns out.
The end of the issue brings it all together - the final text page is hours before the fateful moment in the Adirondacks, bleeding (heh) into the comic pages with a single panel of Brass lying in the aftermath, frame-matched to his lying on the grass of the Planetary hospital's grounds with Snow. After slightly mocking Elijah for asking the advice of a man who's been trapped in a cave, Brass gives Snow some very good advice - break down Planetary's motivation and goals by looking at what they do and who it benefits (and why does the Fourth Man have to be a man?).
But then that last page. Paying back the flashback bleeding over into the comic art, we get one last panel in the style of the pulp text pages showing Brass' glories - he and his allies celebrating a victory together. And then Snow, alone, saying he was busy at the time. And finally the two men, the survivors of the 30s silhouetted against the sunset as their century lurches towards a close.
I've talked a lot about the themes of the issue, but it's well worth noting the actual script and art, which are superlative. Cassaday is improving with leaps and bounds each issue, moving expertly between a traditional comic page and the pulp-inspired illustrations, given an authentic feel by Laura Martin's expert colouring to give that sepia tone. The deep, moody inks on those pages help to keep the authenticity going, as do the smudge effects. They're complemented expertly by Ellis' prose, which captures the overwrought writing style of the time, while the dialogue in the present day sections is naturalistic and genuine.
Overall, this is the first great episode of the story. The pacing works better by virtue of the pulp sections being illustrative rather than narrative, and the conversation between Snow and Brass comes to a natural conclusion. It builds upon what's come before and sets up what's to come expertly as we move to the end of the story's first section.