Chiyo, despite her normally calm demeanor, is easily worked up. Cute things make her pull all-nighters to pursue cuteness. Ninja-related things remind her of her ninja upbringing.

Sekine invites Chiyo to a sleepover at her house, and the other two invite themselves as well. They deepen their bond while Rikka learns more about the quirky cultural activities that take place on Earth.

Hanzo, the assassin sent against Chiyo by her former ninja clan, cannot defeat Chiyo in single combat. He decides to cleverly attack Chiyo through her friends, Chiyo's only apparent weakness.

The four friends go on a trip to Atami, a resort area known for its hot springs and traditional wooden dolls. However, it also featured an eagle-eyed local who could accurately determine Tsubasa's gender.