Two men with the same name work for the same company and are involved with the same girl. One is her husband and the other is her superior. Best Partner focuses on the life of Japan's corporate 30-somethings and the rivalry for success that encompasses their lives. Unbeknownst to each other, Suzuki Ichiro and Suzuki Ichiro both work for the same publishing firm in Tokyo. The only difference in their names is two strokes in the kanji character of their first names. Ichiro #1 marries his coworker, Hayama Asuka. Ichiro #2, who is Asuka's superior, attends the wedding reception and the two Ichiros meet for the very first time. But seeing how close his new wife and her superior seem to be, Ichiro #1 begins to feel anxious about the future