Saki Ayase and Yuuta Asanuma, two strangers who are about to become siblings. This is Gimai Seikatsu or Days with My Stepsister, a mixed media brand that started as a series of Youtube videos by Ghost Mikawa.
But anyway, let's continue this story as Saki and Yuuta's parents meet at a fancy restaurant.
Anyway, Yuuta's father, Taichi Asamura, met Akiko Ayase, Saki's mother, at a bar where Akiko-san was a hostess.
Although I was surprised by that Taichi and Akiko got so close after a night at the bar that they decided to get married. Saki and Yuuta's first meeting was a bit awkward because they treated each other like complete strangers.
Anyway, let's talk about Saki Ayase where she and her mother don't see each other much because Akiko works at night, so she longs for a pure companion.
Meanwhile, Yuuta doesn't show any strong feelings about having a sibling, but he can't help but feel awkward when Yuuta still sees Saki as a stranger. So it will take some time for both Saki and Yuuta to get used to their new lives.
In any case, the Ayase family moved into the Asanuma family as Taichi-san welcomed them with open arms. Also, Taichi didn't clean this apartment himself because his son Yuuta helped him.
I have to say that when I watched the first episode of Gimai Seikatsu, I felt like the mood of this season–a slice of life anime (not a romance anime, by the way) felt a bit realistic but lighter since both Yuuta and Saki are just starting out as siblings.
One last thing, I forgot to mention that Yuuta Asanuma has a part-time job at a bookstore along with Shiori Yomiuri, she is surprised that her co-worker has a new mother and a younger sister.
Anyway, I think they might loosen up their relationship a bit in the next episode when Saki and Yuuta go to the same high school.