This document summarizes the cast and characters of the Korean drama "Our Beloved Summer". It introduces the main characters Kook Yeon-Soo, an ambitious woman with no friends, and Choi Ung, a free-spirited man. It also outlines the supporting characters including Kook Yeon-Soo's best friend and grandmother as well as Choi Ung's manager, father, and mother. In less than 3 sentences, the document provides an overview of the main characters and their relationships in the romantic comedy drama "Our Beloved Summer".