Blood Tithe: Science Fiction

They came for the blood tithe under the crescent moon, knocking on her door and waiting politely until she opened it. "Blood tithe, ma'am," the younger one told her. "We've got you on our list as owing for this two weeks." She nodded. "Yes, I've been expecting you. Come on in. If you don't mind waiting until I finish loading the dishwasher?" The younger one blushed. "Oh, no, ma'am. By all means." The older one watched her with alert eyes. He'd seen people do all manner of things to avoid the blood tithe. But he wouldn't follow her in and he wouldn't watch her. Which was good. She stepped into the kitchen, loudly opened the dishwasher, and then spun to the drawer beside the sink and pulled out the syringe she'd kept waiting. She stabbed it into a major vein in her leg and depressed the plunger, biting back a hiss as the stinging cold nanos swarmed into her blood system. She finished loading the dishwasher, feeling the cold spread--

Inspiration: A combination of working on my taxes and having critted a story yesterday about nanos reshaping people to live in the sea (that's not what this is about).
Story Potential: High.
Notes: There's a war. The blood goes to the war. It's not sabotage that she's doing, precisely, but it forms a link between her and all the soldiers that have her blood. Maybe she can see them. Or sense them. Or something. But there's a lot of them.