Kono Sankaku Love Come wa Shiawase ni Naru Gime ga Aru.

Tenma Yashiro, a regular high school student, learns that Rinka, a classmate known for her cool demeanor, is infatuated with Reira Tsubaki, his childhood friend, who is gentle and attractive. He attempts to help Rinka get closer to Reira. However, Reira ends up developing feelings for Tenma instead. Meanwhile, Rinka offers Tenma a romantic alternative if he does not pursue her. This leads to a complicated romantic situation involving Tenma and the two most beautiful girls in their school. The story explores the evolving relationships and emotions within this love triangle.