WARNING: The following contains spoilers for Episode 10 of Komi Can't Communicate, "It's Just Sports Day," now streaming on Netflix.
Shoko Komi and Hitohito Tadano have been growing close over the course of Komi Can’t Communicate, with Komi even confirming her feelings at least twice. Up until this point, Komi has had no competition for Tadano's affections, in part because he's not popular with girls and in part because the few female friends he has don't have any romantic interest in him. Himiko Agari is too anxious around people and Ren Yamai is only romantically interested in Komi. However, Episode 10 shakes things up a bit.
In the second half of Episode 10 of Komi Can't Communicate, a new classmate named Nene Onemine is introduced as the class vice president. Since Tadano was elected class president in an earlier episode, he's been tasked with doing paperwork. Since his homeroom teacher recognizes he's a bit of a pushover, she hasn't restrained herself from increasing his workload. This causes Onemine to sympathize with Tadano and offer him a lending hand with the paperwork.
With Tadano feeling increasingly overwhelmed by his responsibilities as class president, he finds comfort in Onemine's company. Not only does her assistance help ease his anxiety, but her perception also makes Tadano realize that he's being taken advantage of by their homeroom teacher. However, unbeknownst to both Tadano and Onemine, their exclusive time together is making Komi uncomfortable.
One day when Komi catches Tadano and Onemine walking down the hall together, she catches a snippet of their conversation and hides behind the school stairwell, not sure what to make of her feelings. From the look on her face, it's clear that part of her feels hurt that another girl is monopolizing Tadano's time. At the same time, the blush on her face indicates that part of her also feels ashamed to be experiencing feelings of jealousy. From Tadano's end, he feels as though he's being observed by someone, which makes him feel uneasy.
On another day that Komi observes Tadano and Onemine walking down the hall together, she is spotted by them, with both noticing that she is uncomfortable with their close proximity. Onemine tries to ease the tension by greeting Komi, who flees, leaving Onemine feeling confused. It's not until she helps Tadano with paperwork again that she catches on to the fact that Komi has feelings for Tadano, especially when she decides to stay and help after being told to go home. She then makes her exit so that they can be alone. Komi tries to apologize to Onemine for her behavior the next day, but Onemine confirms that she is aware of Komi's feelings and is rooting for her. This makes Komi blush, and she flees in her embarrassment.
After this brief foray into jealousy, Komi finds herself expressing an interest in trying new things with Tadano she hasn't done before, like going to a photo booth. Najimi Osana and Ren Yamai overhear Tadano reacting to the idea and invite themselves over to partake in the photo booth session. Komi doesn't object to this idea and accompanies her friends to an arcade.
At the arcade, Komi notices a claw machine with cat keyrings but continues with her friends to a photo booth, where they pick out the kinds of photos they want to make. Although Komi doesn't change her facial expression for any of the photographs, she is grateful for having partaken in a fun activity with her friends. On their way home, Komi once again takes a look at the claw machine with the cat keyrings, only this time, Tadano notices that she wants to take one home.
At some point, Tadano goes back to the arcade to get the keyring for Komi, although he doesn't give it to her until three days have passed. When he tells her his reasons for getting her the keyring, he is immediately embarrassed by his own actions. These feelings are not helped by the fact Komi had already asked Najimi to go back to the arcade with her to get a keyring. However, rather than let Tadano's efforts go to waste, Komi offers that they exchange the keyrings as gifts; Komi gives the one she bought to Tadano and accepts the one Tadano got for her. Later that day, Komi is seen cherishing Tadano's keyring, further solidifying her romantic progress.
