We begin with a submarine officer complaining about "standard issue" boots that don't fit properly, and only gradually do we understand why they don't fit properly.
She no longer has standard issue feet.
She also has gills in addition to lungs.
Submarine duty has become exclusively female duty in the US Navy, and apparently other major navies, too. And the women, most of them, are being transformed into mermaids.
No one makes the leap in one transition. It's gradual, repeated returns to the land for more modifications, as the women adapt more and more fully to their new lives as sea creatures. There are also different types of modifications, some shark-based, some jellyfish based, etc. They can do things their landbound fellow sailors can't do, yet the more fully they transform, the better suited they become to their roles, the more completely they are shut out of return to the land or any upward mobility in the Navy. They aren't even comfortable out of the water.
What reason do they have to return to their subs?
This is a brief and fascinating look at one woman's personal progress and shift in perspective. It grabbed me and held on tight, and I think it's well worth your time.