Another great flashback with a great twist in the end which shouldn't have come as a surprise and yet, thanks to splendid execution, I didn't see it coming. My feelings about Ramirez mirror Galen's. We simply don't know enough about her story yet to know for sure where we stand with her. Caelestis dilemma reminds me a bit of the creepy TNG episode where people just couldn't get any sleep. Not sure if the causes here are similar or not. Also noticed quite a few Deltans seem to be involved in this mystery. Of course that could be nothing more than coincidence and I might just be displaying some speciesism here. After all, a lot of humans are involved as well.