I grew up reading European comics, and the ones from Spain, Italy and France especially had a whole genre that were just like 30 Monedas, revolving around some dark mystery heavily steeped in make-believe Catholicism, often with a quest element, so I was really predisposed to love this series, and love it I did.
To explain to a friend with American sensibilities and frame-of-reference I described this as Dirk Pitt dropped into Dan Brown novel with two leads that look like they stepped off a romance novel cover with just the perfect amount of trashiness. If that's a turn-off on its face, this probably isn't the right show for you, haha.
This episode was a really satisfying conclusion (or not, it leaves a door open for a second season, though as much as I love this show, *love* it, in a way I hope that it's finished as the story really ended in a way that shows that some things are eternal, that battle between good and evil in a good old Lovecraft way, and the seduction that can cause people to do really bad things for the right reason.
This was pretty dense in it's pacing, maybe too dense if you aren't paying close attention...on my 2nd watching I noticed some sly almost-Easter Eggs in this one that makes me want to rewatch the entire series again after a bit of time has passed. But every series finale that's a action-mystery should leave you on the edge of your seat. That's another quality I felt, loving the main story-line but how it interweaved with more stand-alone stories within the main a la X-Files, that feel of the old movie serials I watched Saturday mornings as a kid before we got American cartoons here (Blackhawk, Superman, and Tarzan were favourites), and the end of each story arc in those serials was very much like this, as Indiana Jones tried (and of course) succeeded at emulating or as homage.