In Episode 5, Koshi discovers a love letter in her locker, which leads Nokotan to express her disappointment at not receiving any fan letters. The letter turns out to be a challenge from a girl who wants to become the strongest in the city. Koshi faces the challenger and her friends with Nokotan's help but gets overwhelmed until Nokotan changes the situation with her explosive antlers.

After the chaotic battle, Koshi and Nokotan meet at the Deer Club, where the explosion on the school roof is shown on the news. Later, Koshi observes Nokotan in the park and initially feels pity for her but then becomes puzzled by her strange eating habits, where she eats bananas from her antlers. Nokotan's adventures continue at Hino Zoo, where she participates in the "Lord of the Deer" parade and surprises Koshi with her ritual glowing and interactions with the visitors.

Meanwhile, Neko, the student council vice president, tries to uncover Koshi's weakness by investigating the Deer Club. Nokotan misunderstands Neko's intentions and throws a welcome party for her. Despite Neko's discomfort, she joins the tour and participates in unusual exercises led by Nokotan and other club members.

The episode ends with Neko leaving the Deer Club, realizing she has failed to uncover Koshi's weakness.