Title comes from Google describing れき！さつ！as being run over by a car/train.
Summary: Miss comes home to find her pet Marisa and a pregnant scum Reimu. After beating Marisa up to get the truth out of it, she offers Marisa three choices: To take in Reimu and the kids in place of Marisa, Kill off the strays, or be a stray with them. After much deliberation, Marisa picks the third choice, and Miss kicks them out. But right outside her house, Reimu is run over by a car, and Marisa asks to be taken in again. Miss calls it scum and shuts the door in its face.