The “will they, won't they” trope has been a favorite one for romantic movies, essentially since the beginning of the genre. Based on a light novel series written by Kyosuke Kamishiro and illustrated by Takayaki, Shinsuke Yanagi has come up with a series that is based on the concept but moves into an unusual path. As the title suggests, a former middle school couple find themselves under the same roof when their parents end up getting married, without knowing of their children's past. The results are both hilarious and dramatic.
The aforementioned former couple are Mizuto Irido and Yume Ayai, and as the series starts, the tension is quite obvious. Initially fighting about the title of older, sister or brother, that is, their friction extends to a number of fields, including their performances in the first year of high school, where they attend the same classroom. At the same time, however, the fact that their feelings are not exactly gone, and that a physical attraction still exists, with both of them exploiting the fact to gain the upper hand in this “war for dominance”. When Akatsuki, a young man who is desperate to become Mizuto's best friend, and Kogure, who feels even more intensely the same about Yume enter the picture, things become even more complicated. The appearance of Isana, a girl who shares Mizuto's love of light novels and quickly becomes best friends with him, adds even another level, as the three (including Yume) have to face their feelings head on. Lastly, a trip to the village of Mizuto's father sheds more light to the thoughts of the enigmatic young man, as much as the past relationship of the two protagonists, which is eventually presented quite thoroughly through extensive flashbacks.
The narrative style of the series is quite formulaic. The two protagonists almost constantly fight when they are on their own, then some new characters appear that force them to take a more thorough look at both themselves and their relationship, while in between these two aspects, a number of flashbacks explain their past relationship, how it came to be and why it was dissolved. This approach works quite well for the series for the most time, although the flashbacks do become a bit tedious on occasion, additionally because they prevent the actual story from moving forward.
Apart from the main premise, which is quite original and entertaining in itself, Shinsuke Yanagi has included a number of elements that add interest to the narrative. The first is the focus on manga, light novels, and literature in general, with the reference to many famous titles, from “I Want to Eat Your Pancreas” to “No Longer Human” adding a very welcome sense of sophistication to the story, thus preventing it from becoming silly. The fact that Mizuto has the upper hand most of the time, with the story essentially presented more from Yume's perspective, also works well, also because it makes the moment when the cool and detached boy loses his temperament, all the more impactful.
Of course, some sexual connotations do exist here also, while the fan service, even is somewhat organically embedded in the narrative, is still present, with the focus on the impressive boobs of at least two characters, and a number of perspectives that can only be described as peaking (voyeuristic if you prefer) adding even more to that regard. Yanagi, however, keeps things to a leash for the most part, and the title almost never goes into ecchi territory.
As such, Katsuyuki Sato's character design follows the aforementioned lines regarding the girls, while the guys also look quite handsome, although more with a boyish beauty rather than the full-fledgedness of the female ones, at least regarding the bodies, since the faces of all characters are of teenagers. There is an issue here, however, with some characters looking too much alike, as in the case of Madoka and Yume for example, which does become annoying on occasion.
The animation by Project No. 9 follows realistic paths for the most part, particularly regarding the movements of the characters, but there are some impressive moments of intricacy, such as the ones in the aquarium and the festival in the village. The colors are quite intense and bright almost constantly, that give a slight kawaii sense to the whole thing.
Apart from some of the flashbacks that end up being too long, “My Stepmom's Daughter Is My Ex” emerges as a rather intriguing series, particularly regarding the way the main relationship unfolds. It is on the hands of the creators, though, to make the anime even more impactful in the next season(s), particularly if they explore the consequences their potential coming together could have on their family and their social environment in general.
