That was a good story. I really enjoyed the bit of angst, drama, and mystery, especially for a two-parter. Mira's story-telling is surprisingly good, or at least I am enjoying both her story-telling and art more than before and really look forward to any new works from her.
However on a goofy note, 1) I wonder how the mechanics of sex would work between Maho and Rena when they are in their mermaid form?, 2) when Maho says “give it to me Rena,” an image of a fish penis popping out of Rena came to mind (and yes I had to google what one looked like and yes the majority of the entries will be about the penis fish), and finally 3) i wonder if mermaids spawn like other fish or ovulate/give birth like humans? I speculate Princess Mio gave birth to Maho since the princess was in human form, but what would have happened had she been in the sea? hmmm… enquiring minds would like to know.