A lot has happened for Nagi Umino and Erika Amano: they were swapped at birth, learned of their engagement, and have started living under the same roof. The two now share their home with Nagi's sister, Sachi, and his crush, Hiro Segawa. Despite this unusual domestic situation and frequent quarreling, the group is beginning to settle into a life together. However, the return of Nagi's childhood friend Ai Mochizuki to Japan complicates things. Ai suddenly declares her intention to marry Nagi, and although he turns her down, she is committed to having him all to herself. Now with four girls around, each with their own thoughts about him, Nagi must figure out his own feelings and the best way forward.
Episode 1
Who Was Umino-kun's First Love?
Jul 8, 2025
Hiro moves in with Nagi, Sachi and Erika. Friction arises, but they're reminded of what happiness might mean.
Episode 2
Onii Confessed to You, Didn't He?
Jul 15, 2025
Hiro is kidnapped and Nagi immediately sets out to save her.
Episode 3
That, but Times a Hundred
Jul 22, 2025
Nagi is suddenly hit with the truth about Ai’s real objective.
Episode 4
I See You're All Together
Jul 29, 2025
Hiro is preparing for a festival that's about to be held at her shrine.
Episode 5
It's My Life, Too!
Aug 5, 2025
The world now knows the face of singer Mochizuki Ai, who created the song “Arc Fault.”
Episode 6
There's No Way I Can Be Normal!!
Aug 12, 2025
Nagi and Erika are trapped in a hotel room by her mother, who seems to be playing with them.
Episode 7
It's Ours to Build!
Aug 19, 2025
Episode 8
No Such Thing as a Meaningless Kiss
Aug 26, 2025
Episode 9
The Real Enemy is Sachi-chan!!
Sep 2, 2025
Episode 10
I Know, Nagi-kun! Let's Take Pictures for Memory's Sake!
Sep 9, 2025
Episode 11
I Found Him Attractive for the First Time
Sep 16, 2025
Episode 12
Thank You for Falling in Love with Me
Sep 23, 2025