What an interesting development! The thing without a soul doesn't want Paul Stoddard's soul, it wants Carolyn. Not just her soul, apparently, but the whole kit and caboodle. Maybe her soul's no good to the thing unless it tears her soul out of her with its own soulless hands.
Early in this episode, I was thinking about how annoying it is that people in movies act crazy about real threats so so that nobody believes them and nobody helps them address the problem. Then I thought about what we have learned so far about Paul Stoddard - i.e. that he's a coward - and I forgave the Dark Shadows writers.
What exactly happened 20 years ago? Did Paul Stoddard have that conversation in the Blue Whale? It seems quite possible to me that he did not, and that the memory was somehow created. The Leviathan gang doesn't seem terribly honorable to me. On the other hand, what would be the point of creating the memory? Couldn't they just grab Carolyn in the same way that they have, psychologically, grabbed Barnabas, Philip, and Megan? Or maybe the bargain with Paul Stoddard was necessary because they needed Carolyn to be given freely. (Handed over like a sack of potatoes and without her mother's consent, but never mind about that.) Maybe something in the book decreed that Carolyn must be given, not taken. How, then, did they pull off that 20-year-old conversation in the Blue Whale? And why did it have to be Carolyn who was given?
Also, assuming that the encounter in the Blue Whale did happen, was it the cause of Paul leaving Collinwood? If it hadn't happened, would Paul have stayed at Collinwood, never brave enough to leave and strike out on his own (with the help of what he could steal from his most precious possession), so that Elizabeth wouldn't have whacked him with the poker and wouldn't have let go all the servants (poor innocents) and wouldn't have stayed inside the Collinwood estate for a couple of decades?
Did the Leviathans cause the pentagram to get lost? If so, does that indicate that, contrary to what the sailor said to Paul Stoddard, sitting inside the five-pointed star wasn't going to help him?
Meanwhile we've got Julia making a small start on figuring out what's going on, and Barnabas unable to stop her because he's too driven to be able to hide his feelings successfully. I love it.