During lunch, Tsubaki notices Ueno grinning like a fool and asks him why. Ueno is excited because tomorrow they will be switching to their summer gym uniforms, which means... the girls will be wearing less clothes during gym class compared to the track suits they wear for the winter season. Tsubaki doesn't get it at first, until he imagines Urabe wearing her gym uniform. Just then, Oka approaches Urabe and offers to eat lunch with her. This is unusual because usually Urabe just sleeps during lunch.
Oka proceeds to eat lunch beside Urabe as Urabe goes back to sleep. Surprisingly Urabe wakes up because she smells something good. Oka feeds Urabe a bit of her omelette, saying she is a great cook. Oka then feeds Urabe other parts of her lunch, all of which are delicious. After school, Tsubaki asks Urabe if anything happened with Oka. Tsubaki says he is happy to see Urabe making a female friend in the same class with them. Urabe says she doesn't need friends because she has him as her boyfriend. Tsubaki tastes Urabe's drool for the day. Oka sees this happening. That night, Tsubaki has a dream where Urabe is feeding Tsubaki food just like how Oka was feeding Urabe in class.
For phys-ed the next day, the guys are inside doing judo, while the girls are outside running relays. Urabe accidentally trips over another runner and scraping her knee, so Oka offers to take her to the nurse's office since Oka is the class' health representative. Urabe tries to say it's not that bad. Oka retorts by saying as a girl she needs to take care of her appearance. Ironically, Tsubaki scrapes his forehead while doing judo with Ueno, turns down going to the nurse's office and Ueno says "Yeah! Men wear scars like medals of honor!"
The nurse isn't in the office, so Oka treats Urabe's knee herself. Oka takes a bottle of soda from the fridge and starts drinking it, offering Urabe a sip as well. Oka says she wants to be friends. Weirdly a wound appears on Oka's knee, just like the one Urabe has. Urabe does a test: she makes a cut on her hand and then has Oka taste her drool. After doing so, a similar cut appears on Oka's hand. Urabe concludes that they share a drool bond. The reason Oka has a wound on her knee is because they drank from the same bottle. Oka explains that ever since she saw Urabe and Tsubaki after school that one day, she had been interested in learning more about Urabe. Urabe repeats that she doesn't need any friends. She also adds that Oka should treat her wounds because as a girl she shouldn't let them scar. So it looks like Oka has had some influence on how Urabe thinks.
The next day, Ueno catches Tsubaki on the way to school. Ueno is grinning like a fool again because he plans to telepathically tell Oka that he wants to secretly eat lunch with her. During lunch that day, Urabe exits the class, followed by Oka. Oka has Urabe taste her drool, saying that she will learn something about her relationship with Tsubaki. Urabe does so and says the drool is sweeter than anything she has tasted before. From this reaction, Oka concludes that Tsubaki and Urabe have not gone very far yet because when Oka produced that drool she was thinking of the time Ueno and her first kissed. Oka changes topics by inviting Urabe to have lunch with her, saying she cooked a lot more than normal today. Urabe's stomach growls and explains that after eating Oka's cooking, she started getting hungry during lunch, which never happened before.
As Ueno is lamenting to Tsubaki about his failed attempt to telepathically connect with Oka, they spot Oka feeding Urabe outside. Tsubaki is still a little puzzled about his mysterious girlfriend saying that she doesn't need any friends.