A story of the sea, youth, and flaming passion. Yoon So-ra's dream is to become a dolphin trainer. Jang Tae-poong has a sad childhood. Jang Tae-hyun is Mr. Perfect on the outside, but feels inferior and lonely on the inside. Min Joo-hee is the Jang brothers' childhood friend. These four people share their love, dreams, and pain as they mature over the summer.
Played by Lee Wan
Fearless and proud, Tae-poong is the biggest dunce of the 21st century. He is the son of CEO Jang, head of Korea's largest leisure company, "Hanpia," and CEO Jang's first love. He becomes a lifeguard to redeem himself of his reputation as a walking disaster. He is honest to a fault as he spits out whatever comes to mind. He does not know how to give up. Because his mother abandoned him when he was a child, he has an unbearable loneliness buried deep inside him. He also has a soft spot for his first love, Joo-hee. Macho man Tae-poong meets "tacky" So-ra, and they butt heads at every turn.
Played by Lee Cheong-a
Having grown up near the East Sea, So-ra is a strong-headed, warm-hearted girl who wants to be a dolphin trainer. She loses all her money she had saved to go to Australia to study dolphin training because of Tae-poong. She is very friendly, good-natured and sharp as a tack. She is also an excellent cook. That is why she does a great job running the small motel business with her grandfather. However, she is naive and innocent enough to believe that when she meets "the one," she'll hear the bells of destiny chiming. She meets her so-called "Mr. Right," Tae-hyun, and her archenemy, Tae-poong, all in one crazy summer.
Played by Jun Jin
Born with outstanding brainpower, good judgment, and diligence, Tae-hyun is the heir to "Hanpia." He is Tae-poong's half brother, the son of the current Mrs. Jang. He is relentless in becoming the best at what he does, whether it be love or work. He has no fantasies about love or marriage, because he knows the ugly rot festering beneath the perfect facade of his family. However, So-ra's goodness starts to rub off on him and he begins to open his heart. But his fianc?, Joo-hee, will not let him go without a fight.
Played by Kang Jeong-hwa
Joo-hee works as the Director for Planning and Cooperation at Hanpia Hotel. She is the only daughter of widower Chairman Min, the owner of a major construction company. She has it all: looks, intelligence, and wealth. She grew up with the Jang brothers, and she plans to marry the successful and reliable Tae-hyun. She believes that love is just self-hypnosis and continues to express her love for Tae-hyun. She feels hurt by Tae-hyun's cold exterior because he thinks love is just another business transaction. When So-ra suddenly appears in all their lives, Joo-hee is jealous because So-ra seems to have captured the Jang brothers' hearts, which Joo-hee thought belonged to her.