There was an inland sea where the north sea should have been. It touched Russia on one side.

Sara and Marilla and I, along with a smallish group of other people, were scuba diving in it for some reason.

The place where we went in was very deep, and maybe halfway down there was an ice shelf that we would not need to go below, but I was a little worried that Marilla would try, and, on a steep cliff that went all the way from the surface to the deep depths, a hotel, or some kind of staging location.

The scuba diving didn't feel like an especially big deal. It felt like going on a canoe trip with the Outing Club. Marilla swam around on her own just fine. Maybe better than Sara and I did.

The swimming wasn't done for its own sake, I don't think, but we had some kind of mission, or maybe we were just going camping, but in order to get to our destination we had to swim around in this sea, cut through some ice and pop out somewhere, and then do some walking.

Our group may have split into two or three subgroups at some point, but then we ran into each other again along the trail.