In the story, Hiyori's grandma passed away. For his daughter who cried every day, Hiyori's papa built a grandmother-model robot named Wasimo. The nostalgic "katakatakata" sound Wasimo makes when it walks comes from the same false teeth that Hiyori's grandma had. Wasimo walks faster than a snail, but slower than an excited snail. Still, Wasimo can actually run faster than a speeding bullet train. The story follows this strange Wasimo as it meets all sorts of people and has all sorts of experiences.

[Source: Akiba Souken]

A grandfather-model robot named Wasija arrives on Earth from space. Wasija transforms everyone into a robot with mechanical bodies in order to "save the Earth." However, now everyone requires oil for energy. Grandmother-model robot Washimo confronts Wasija in order to restore everyone to normal.

[Source: Anime News Network]