Bokura ga Ita follows Nanami Takahashi as she enters high school determined to make new friends and find her place among her classmates. There she meets the shy Yuri Yamamoto, who tells her about Yano Motoharu, a popular boy in their class with a complicated reputation. Yuri has little interest in him because of his past relationship with her older sister Nana, and Nanami initially dislikes his attitude as well. Even so, Nanami's opinion begins to change as she and Yano spend more time together, and their uneasy connection slowly turns into dating.
What unfolds is a fragile romance shaped as much by hesitation as by affection. Yano struggles to open up to Nanami, still carrying the weight of his relationship with Nana and the emotional damage it left behind. As their bond deepens, Nanami and Yano have to navigate jealousy, silence, misunderstandings, and heartbreak while trying to protect something neither of them can easily put into words. The series traces how young love can be tender, painful, and difficult to hold onto, even when both people know exactly how deeply they care for each other.