Spring Waltz is the fourth and final installment of Yoon Suk Ho's season drama series. The first drama was Autumn Tale, followed by Winter Sonata and Summer Scent. In order to escape debts, Lee Su-ho and his father run away to the family's home town, a small island isolated from the rest of the world. While Su-ho's father goes on a short trip, he leaves his son under a friend's care. Afraid his father would not come back, Su-ho begins collecting money to buy his own boat ticket. However, his plans change after befriending Suh Eun-young, the father's friend's daughter. Eun-young was born with a sickness and spent most of her childhood at home. She constantly prays to make a friend, and she finds this friendship in Su-ho. It is at this time that Su-ho's father returns from his trip. It is then revealed that surgery is needed to cure Eun-young's sickness. The money saved by Eun-young and her mother, however, is stolen by Su-ho's dad as he, once again, runs away to Seoul, casting a blanket of doubt and mistrust over Su-ho's character. Still, Eun-young believes in her friend and oppa and they continue to care for each other. However, after a tragic accident, Su-ho takes up an offer with two wealthy people, who agree to pay for Eun-young's surgery, under the condition that they get to take him in as their son. Eun-young and Su-ho then separate without goodbyes... and see nothing of each other until fifteen years later, when they are known as Park Eun-young and Yoon Jae-ha. The plot is then thickened, with the added prescence of Phillip, the half-Korean who's popular with the ladies, and Song Lee-na, who is Jae-ha's childhood friend. In the midst of a complex love triangle and Jae-ha's stubborn parents, is it possible for the two to fall in love once more?