Episode 4 of "My Tiny Senpai" begins with Hayakawa preparing to attend an otaku event in the city and grumbling about the long commute. Unexpectedly, she runs into her manager, who recognizes her passion for otaku culture—a revelation that leaves Hayakawa flustered.

Later that night, Hayakawa attempts to draft a manga manuscript, but her efforts prove futile despite staying up late. The next day at work, her colleague Shinozaki notices her exhaustion, prompting manager Akina to invite Hayakawa out for dinner. Surprisingly, Akina expresses interest in joining her at an otaku gathering, a suggestion that leaves Hayakawa stunned.

The ensuing conversations revolve around Shinozaki and Hayakawa’s friendship and various workplace dynamics. After dining with Shinozaki, Hayakawa feels relieved that Akina remains unaware of her love for BL manga series—unbeknownst to her, Akina and another colleague, Katase, have overheard this revelation.

Later in the episode, Halloween celebrations unfold, with Katase and Akina dressed festively. Hayakawa feels uneasy when Akina insists she wear cat ears. A humorous exchange about Halloween treats ensues between Shinozaki and Katase.

Finally, Katase reflects on Shinozaki’s growth within the company and embraces him warmly. Seizing the moment, Akina probes Hayakawa about her feelings for Shinozaki.

Overall, the episode focuses on the budding relationships between the characters, particularly Hayakawa and Akina. Despite the charming and humorous interactions, the characters’ connections still feel superficial.