Bad Thinking Diary

High-spirited Kim Min-ji and striking beauty Kang Yu-na have been best friends since high school. Now in college, their friendship has deepened enough that Min-ji feels comfortable telling Yu-na she had a vivid and steamy dream about her. Min-ji is oblivious to the effect her confession has on Yu-na, but others notice that Yu-na is in love—and even seek to take advantage of it. Min-ji, new to love and eager for experience, accepts a date with a man. But memories of her lustful dream and the way Yu-na makes her heart race refuse to leave her mind. Filled with confusion, Min-ji decides to confront Yu-na with these feelings. While Yu-na is overly elated to discover that her love might be mutual, Min-ji's uncertainty complicates their relationship. Ultimately, Min-ji must choose between pursuing the man interested in her or her own increasingly passionate affections for Yu-na.

Minji and Yuna were always together. From the age of 17 to now, until the age of 21, they have been each other’s best friends. From that day on, the relationship subtly changes. It started with Minji’s strange dream in which Yuna appeared! Their relationship begins to turn into something other than best friends.
Unrequited love, excitement, and obsession. “Bad thoughts” that grow one after another in each others mind.
Where will our “bad thoughts”, which started on a lush college campus, end up?