本剧改编自YONEMAI创作的人气漫画，系列累计发行量已达20万部。不得志的作家·吉田政宗（中泽元纪 饰）误以为自己与交往了10年的恋人桃香的关系即将走到被甩的“尽头”，于是在逃避心理下，与在拼桌酒吧偶遇的一位女性共度了一夜。故事以政宗的优柔寡断所引发的“三角关系”为主线，在卷入各自恋爱情感的过程中不断加速发展……一边是10年岁月的重量，一边是一瞬间的过错。在各种思绪激烈碰撞之后，他们所选择的“幸福”又会是什么模样？这是一部真实描绘人性狡猾与纯粹大人恋爱的群像剧。

Akoko has a straightforward and honest personality, and acts immediately on what she thinks, unable to lie to herself or others. By her side is her best friend since third grade, Miyuki, who she has known since they were in elementary school. On the first day of school at the start of the new semester, Naoki, the most popular boy in school and the driving force behind attending the all-girls school, has unexpectedly repeated a year and is now in the same grade as the two of them! Akoko falls in love with Naoki at first sight and begins to approach him in a very straightforward manner. Miyuki declares that she doesn't like him, saying "I think he's cool, but it doesn't feel like love," but Akoko senses Miyuki's suspicious movements. The first to strike wins! She confesses her feelings to Naoki.