It all started when the famous Kwon Yuri accidentally read the diary of her number one arch enemy, Jessica Jung. In Seoul Arts University, Yuri and Jessica are the known 'rivals'.

4 years ago, they started out as bestfriends. But eventually, their friendship was torn away and was replaced by a new relationship, and that is being 'enemies'. They are competing in everything: in academics, in sports, in co-curricular activities, and even in love life.

Yuri always thought Jessica was bossy, spoiled, and very self-centered.

Jessica thought Yuri was arrogant, irritating, and a player.

Both girls hated each other and did everything they can to point out all the negative things about each other.

But what they didn't know and expect, is that hate can also turn into love.

Yuri 'accidentally' read Jessica's diary, which was again, 'accidentally' placed inside her bag by an unknown person. There, she began reading Jessica's written journals and she saw something very interesting.

Jessica is actually crushing on someone.

And no it's not a boy.

Yes, it's a girl.

She has long black hair.

Tan skin.

A y athletic body,

tall height,

And a very charming smile.

Who else has all those characteristics?

No one else but Kwon Yuri.

Jessica is actually crushing on her?

This made Yuri's heart feel somewhat different.

Jessica actually crushing on her?

Because of this, Yuri actually thought of an evil plan.

She'll use the diary to blackmail Jessica.

If Jessica wants to have her diary back and keep Yuri from blurting out her secrets from everyone, she has to follow one condition of Yuri.

She has to be Kwon Yuri's girlfriend for an entire week.