This is Chapter 4 in Volume 1 of A Place Further Than the Universe
Yuzuki asks Shirase to go to Antarctica in her place. Then her mother arrives, and rejects that idea. Yuzuki thinks about how much trouble she is having with making friends at school, and insists that she isn’t going to Antarctica. She happens to run into the girls in front of her place, and realizes that her mother has sent them to change her mind. She explains to them about not having friends. Kimari gives her a hug. Yuzuki realizes that this is the first time anyone outside of family has done that. That night she dreams of Kimari inviting her to Antarctica. In the morning, she sees on her phone that her prospective friends from school have left the chat group, leaving her all alone once more. Kimari, Shirase, and Hinata then appear at her door wanting to accompany her to Tokyo for the day. This leads her to call her mother and agree to go to Antarctica, as long as it’s all four of them together.
Megumi gets a text from Kimuri telling her the news. She isn’t sure why, but she is bothered by this development. She happens to meet Kimari’s mother out shopping, and they discuss the girls’ relationship since kindergarten.
This chapter is based on Episode 3 of the anime.