Seunghyun, the coward playboy, and Jiyong, the forever third wheel. They are secretly in love with each other but are too stubborn to admit it to themselves, let alone to each other. Will they finally have a chance for romance?

The story revolves around the lives of Kwon Jiyong, Choi Seunghyun, Dong Youngbae, Min Hyorin, Lee Seungri, and Park Dara, who are all best friends since high school.

Kwon Jiyong, the forever third wheel. He is an Animator for an animation/cartoon company. He is very artistic and has a hidden talent in rapping/singing and also has a phenomenal taste in fashion. He's internet-famous, but as an anonymous blogger who writes relatable stories/quotes - mostly about being bitter and single. His blogs also include his beautiful works of art in a section called "FROM THE [He]ART". He doesn't reveal his true identity because he has very low self-esteem and being anonymous boosts his confidence to say/express his true feelings. He has everything but LOVE. Sure, he has his family and friends, but he has that desire to love, to be in love. He is in love with love itself and is a major hopeless romantic. The thing is, he doesn't even have someone special in his life to make them feel his love the kind of love you can't find in family or friends, the kind of love we all aspire to have, the romantic kind. Everybody in his life has a partner, making him the ultimate third wheel. He's the third wheel to everyone! He is the third wheel to his parents, the third wheel to his sister and her husband, and most especially, he's the third wheel – no, the fifth wheel – of his friends because of an unknown reason, 4 out of 6 of them decided to "couple-up"

Choi Seunghyun, the coward playboy. Best friend of Seungri since forever because their dads are best friends too, they've known each other their whole life and even share the same name. Super good-looking, charming, and talented. He knows his way with the ladies. He's the high school heartthrob of their school not only because of his looks, but also his insane rapping skills that can make any girl's drop. He's also good at beatboxing which is another plus point for the ladies. Because of his charisma, he tends to have different girls to flirt with every week which is why his friends would call him a playboy. He's sweet and a very gentleman, that's why you can't blame Hyorin and Dara, if, for a time, they fell for him. By nature, he is a very sweet guy, it's innate to him being caring and touchy-feely, maybe that is the reason some girls assumed that Seunghyun likes them when in reality, that's just how the way he is. It comes out naturally, and he's not aware that some girls fall for it. He just keeps on doing what he does. No intention of making them fall for him, and definitely no intention of catching them. It may sound harsh, but it's true. That is the common mistake of the girls and guys who fell for him and became hopeful. In reality, he is not really a “Playboy”, he is just being - well, he is just being Seunghyun. He is just misunderstood.

Lee Seunghyun (Seungri), jobless but super-duper rich. Easy go lucky and go with the flow kind of guy. His dad owns almost half of Korea's gas stations and convenience stores. He inherits a resto-bar where he and his friends always hang out. He's not into the business though, but he sure loves sports. His favorite sport is swimming and he loves joining competitions. He has been very faithful and very much in love with Dara ever since high school and has been planning to propose to her soon. Being a bum always gets in the way of their relationship, and they always fight about it. Then one day, he starts looking for a decent job and gets down on one knee and proposes to the love of his life, Dara.

Dong Youngbae, Chef, and Hyung of the group. He loves cooking for his friends, most especially for her long-time girlfriend, Hyorin. He grew up in the States and just moved back to Korea when his brother graduated from high school because his parents believed that the education here in Korea is better. He is the most responsible guy in the group. He is always the designated driver, the “Hyung” to go to for advice, the good listener, and the secret-keeper. He is close to everyone in the group.

Park Dara, one of Jiyong's best friends since preschool. Girlfriend of Seungri. Works in a Music Television Program as a Producer. High school Valedictorian and prom queen. The ideal girlfriend. She has the looks, the brains, and the money. All their girl classmates wanted to be like her, and all the boys wanted her, but, only Seungri got her heart.

Min Hyorin, also one of Jiyong's other best friends since preschool. The long-time girlfriend of Youngbae. She's a volleyball player. Star player since high school up until college. She acts boyish, but she dresses very girly. She's a fashion photographer and works for a fashion magazine.