A maid suddenly appears at the house of high school student Hitoyoshi Yokoya, asking to be hired. However, her background as a former assassin makes Hitoyoshi think twice. From this fateful encounter, their lives together will forever be changed.

One day, Hitoyoshi is compelled to adopt a puppy that was left in front of his home. However, the maid has a childhood trauma involving dogs. Watching the two interact, the maid soon sees the world in a new light, even wishing to be "normal" herself.