In the first installment of the Endless Love series, two families must come to terms with a mixup at birth, and at the center of the drama are Yoon Joon-suh, Yoon Eun-suh, and Choi Shin-Ae, three children who must deal with the aftermath. A car accident reveals that Eun-suh's blood type is in fact different from the rest of her family, and that Choi Shin-ae, a peer at her school, is the rightful daughter to the Yoon family. The two girls both return to their respective households, with Shin-ae moving up into wealth and prestige, and Eun-suh stepping into poverty, being left behind in Korea as the Yoons go abroad. Years later, the families come together again in Korea, and former bonds between Joon-suh and Eun-suh are rekindled. But Shin-ae and the two families forbid the former siblings from developing a relationship that crosses that old line. Starring Song Seung Hun, Song Hye Gyo, Won Bin, and Han Chae Young.