Disclaimer: I do not own Supergirl or anything to do with DC. I do not make any money from the writing of this story.
*****
Kara Danvers, a.k.a. Supergirl, was bored. She'd had quiet nights before, but this had to be an all-time record low criminal activity. Which on the one hand was good because it proved that people were thinking twice about committing crimes in her city, but on the other hand it led to incredible boredom. Normally there was some petty criminals stupid enough to try something, or something that resembled a threat stepping up to her, but this time there was nothing.
Not even an accidental fire for her to save a few people from. And the second she heard about something in a different city in other superhero dealt with it, which got irritating after a while.
At least she comforted herself with the knowledge that once she returned home to be greeted by her loving big sister, and that definitely wouldn't be boring Kara thought with a smile. Thoughts of what exactly they would do had been playing throughout her mind throughout the day, as they always did, but it had been particularly useful as her working day had turned out to be just as dull as her time as Supergirl.
Ms Grant hadn't given her much to do, which was a startling contrast to last week, just before they had sex for the first time. Kara smiled again as she thought how that first time had basically been repeated almost every night this past week, except for the weekend which was sister-sister time, but tonight it was Ms Grant who was busy and Alex who was available. Almost like they had a schedule or something.
Whatever the case it was tough for Kara not to change her schedule and fly straight for her sister Mistress, but somehow she was able to hold back and spend at least a few hours patrolling the skies before returning home for the treatment she so desperately needed. Although when she finally did she got like the best surprise ever, as not only was Alex waiting for her, but so was Ms Grant.
Having a really good feeling about this it was tough for Kara to contain her smile, but while this might mean she would have a really good time later she had to remember that Ms Grant didn't know the truth, and therefore she quickly needed to come up with an excuse of why she was here.
"Alex Danvers, Ms Grant, what a wonderful surprise." Kara beamed, "I was just looking for Kara Danvers. Have either of you seen her?"
Cat smiled, "Hello Kara."
As her sister looked surprised, then gave her a look, Alex sighed, "Don't look at me like that. She already knew."
"And I just spent like an hour signing a ridiculous amount of disclaimers for the DEO, promising not to out you or them, or the kinds of things your sister and I do to you." Cat said dryly, taking a long sip of the expensive drink that was in her hand before adding, "Alex insisted on that last one."
"The point is, you were sloppy Kara." Alex glared angrily.
"Please, it's just glasses in a ponytail. I don't see why you people think that would work." Cat pointed out, "I mean sure, perhaps the people passing on the street wouldn't notice, but anyone who spends more than a few seconds with you has no excuse."
"It's more effective than you might think." Alex said dryly, "Besides, do you want an excuse to punish her or not?"
"We don't need an excuse to punish her darling, where her owners." Cat chided her new friend and Co-Mistress, before turning her attention back to her assistant, "Isn't that right, Supergirl?"
Smiling nervously Kara replied, "Yes Ms Grant."
"Good. Now we're all on the same page..." Cat said, briefly downing her drink and putting the last down on the table beside her walked forward slightly and ordered, "Get on your knees."
"Yes Ms Grant." Kara gave another nervous smile before falling to her knees in front of her boss.
The sight made Cat's breath hitch, then she took another step forward so she was directly in front of Kara and then started sliding her hand through her hair, "I've waited a long time to see you like this, in your pretty little costume. So don't even think about removing it! We'll move it aside as needs be, but tonight I'm fucking Supergirl. Understand me, Kara?"
"Yes Ms Grant." Kara said softly.
"Stay where you are Kara." Alex ordered softly.
"Yes Mistress." Kara quickly replied.
"It's Mistress Alex, tonight." Alex corrected.
"Then yes Mistress Alex." Kara smiled happily.
As she spoke Alex stepped forward to reveal Kara's kryptonite collar, Kara happily moving her head to the side to make it easier for Alex to strap it around her neck. The second it was near enough to her she felt weaker, and the second it was strapped around her neck she had to grit her teeth to stop herself from whimpering.