The re-read continues, as I got sucked into this series again.
There's some fun stuff here, with the introduction of some Eastern esoteric traditions and Buddhist thurbas. Nazis, of course, always make the perfect villains, so those ties certainly ramp up the threat, even if what we're actually seeing has more to do with historical Nazis ties to occultism rather than anything to do with a modern ideological affinity.
There's a secondary plot thread that resonates nicely as a counter-point to the primary threat of the anti-Buddists; Adam & Noel investigate "spooky" deaths via unexplained car crashes. It's a much lower-level threat, but a good storyline showing more of what the regular work of Adam's Hunt is: dealing with psychic spillovers, healing those who don't understand or can't control their gifts, and managing that higher Law. There's echoes of our first introduction to Peregrine in this B-plot, and it's nice call-back, even if there's a little too much of the "hypnotism fixes everything!" associated with it. But clearly not every threat or problem is of the earth-shaking scope as the A-plot, so it's nice to see the more daily grind.
The lost Nazi submarine, the return of Francis Raeburn as a foil to Sir Adam, and the dangers of allowing occult treasures previously controlled by the Nazis back out into the world makes for a fairly gripping story. On the other hand, Noel & Peregrine are regulated to sidekick status at best, where they're not mostly sidelined altogether in favor of the glorious Sir Adam (he said with a certain sarcasm). The renewed focus of the perfection of Adam is back in full force here and it's still a little dull. While I'm fairly bored with the modern trend towards massively flawed, unlikable protagonists (I can't even classify many of these as anti-heroes), the unmarred perfection of Sir Adam isn't as compelling as it used to be, especially after 4 books. Adam's problems are things like "my gorgeous, perfect surgeon girlfriend had to go back to America to tend to her dying father for a while so I can't marry her yet" which isn't enough to lend much sympathy, since the party deserving of it is Ximena, not Adam. He's rich, handsome, accomplished, and noble with a huge network of contacts, loads of dedicated and loyal friends and the only real problem he has is black magicians occasionally try to kill him. which is something he's willingly taken on, and they always seem to lose pretty badly anyways. He's a little too good, and not really human enough.
These flaws pop up more noticeably in a binge re-read than they did on first pass, and part of that is simply the publishing schedule. With a year or 2 between books it's a little less noticeable and memory fades some. repetition tricks to refresh memory of early books or reinforce character details are annoying in the binge but were probably necessary for the original publication. And I suspect the perfect Adam Sinclair grated much less with distance between his adventures.