A Sour Operation? / Is This a Test of Courage!? - S1.E4

Suspicious about the relationship between Haruka and Yuu, Mitsuki asks their classmates, Yuzu Iizuka and Kaede Ikeno, to keep an eye on them and make notes any suspicious behaviour. Later, the girls get together for a test of courage, where Mitsuki attempts to tail Haruka and Yuu, but gets mistaken by Yuu for a ghost, leaving her so scared that she asks Haruka to kiss her to calm her down.