One dinner-table announcement from dad and every hallway in that Setagaya mansion turns into a minefield. This is Reiji Miyajima writing the thing Rent-a-Girlfriend never let him do: actual movement. Where Kazuya stalled for a hundred chapters, Arata gets the blood-relation rug pulled out in episode one and the five sisters have to decide, on screen, what they were really feeling this whole time. Yes, the archetypes are off the rack, tsundere, tomboy, otaku, imouto, unshakable onee-san, and yes, the pivot from sibling to suitor happens faster than any human brain works. But the animation actually holds up, the faces sell the moments the writing rushes, and the discomfort is the point rather than an accident. You will either drop it by episode three or defend it in a group chat at 2am. There is no third option.

Arata Shiunji lives under the same roof as five relentless sisters in their sprawling Tokyo mansion, constantly serving as their personal punching bag. He fantasizes about peace and quiet, about a life where he isn't the family's favorite target for teasing. Then his father drops a bombshell: Arata isn't actually their biological brother. The revelation complicates everything. Now that the biological bonds are gone, what exactly holds this chaotic household together? Are they still a family if blood doesn't connect them? The siblings agree nothing will change, but the sisters soon begin to approach him with feelings that go beyond sibling affection. Arata, who values his family above all else, must find a way to keep their bonds intact. What unfolds is a romantic comedy about a house full of siblings whose relationships are suddenly put to the test.