WARNING: the following contains spoilers for Episode 4 of My Senpai is Annoying, "Someone Who'll Be By Your Side," now streaming on Funimation.
During the winter season, Futaba and her senpai, Harumi Takeda, slowly build a more meaningful relationship beyond kohai and senpai in the office. Already, Futaba and Takeda have exchanged favors, with Futaba owing her senpai many more favors than he owes her. Futaba feels that she is falling behind, but flu season changes all that.
Futaba already feels insecure about her role in the office and her work, and then she falls ill and becomes bedridden for a few days. She isn't too proud to accept Takeda's help, though, and when the time is right, Futaba repays him with not just one, but two favors.
Futaba falls ill after walking around outside in the cold, and she texts her co-workers, alerting them that she must take the day off. Harumi Takeda visits and gives her energy drinks and snacks, and then Futaba invites him in to help her some more. Takeda generously prepares hot udon noodles for her, and Futaba feels grateful until she realizes Takeda can easily see how childish her apartment looks. She fears that Takeda and her co-workers would sneer at her for having stuffed animals and old high school photos on a bulletin board, establishing yet another insecurity of hers. These two factors set Futaba even farther back in the quest to impress Takeda as an employee and as a lady.
Futaba and Takeda meet up again at the office, and Futaba doesn't like how her co-workers know about Takeda's helpful visit. Despite her multiple insecurities, Futaba still has her pride and dignity, and she also has a tsundere streak. She doesn't want people to know about her amorous feelings before she is ready, and it doesn't help that Takeda loves to blab. He had already informed his co-workers of his visit to Futaba's apartment, much to Futaba's chagrin. Futaba feels desperate to keep things under wraps, but at this rate, she never will. Secrets just leak right out.
Futaba and Takeda go out for the afternoon, and Futaba gets her chance to catch up with Takeda. She learns that he lacks a smartphone and can't easily use one, and he's been using an outdated office phone all this time. Futaba lends Takeda a hand and helps him find and buy a smartphone at a shop, and they exchange contact info. This way, they can reach each other more easily, including text messages. Takeda, however, struggles with even the basics, and it takes him hours to send Futaba his first-ever text message. Futaba and Kazama can hardly believe that the smart and capable Takeda could get overwhelmed like that.
Then, Takeda takes a day off work, having caught a bad cold himself, and Futaba volunteers to secretly help him. She prepares a hot meal for him, and Takeda remarks on its quality and taste. He gently teases her about making a great wife someday, but despite his jabs, Takeda is the needy one this time, and Futaba feels satisfied that she fully repaid him for helping her earlier. That, combined with the phone, allows Futaba to catch up with Takeda, as hoped, and not feel so helpless. His invincible facade finally has cracks in it, and despite Takeda telling everyone at work about Futaba's secret visit, Futaba feels closer to Takeda and offers to cook for him again someday. She feels brave enough to take the next step without needing to repay a favor first, and that's huge.