Bad Thinking Diary summary: Min-Ji and Yu-Na, who have always been together. From the age of 17 to the age of 21, they are each other’s best friends. From one day the relationship is subtly different. Min-Ji’s wild dream about Yu-Na started! Their relationship begins to change into something other than their best friendship. Unrequited love, excitement, and obsession. “‘bad ideas” growing up in their own minds. Where will their bad ideas, which began on a lush college campus, finally arrive?