The Sweet 18 Ji-eun has been BFF's with her friend next door Min-cheol for more than 10 years. Normally there isn't "just friendship" between boys and girls but they have been claiming that they're just friends for past 10 years... However they come to school together, and gets out of school together, visits each other when each other is sick, and when they go play the both of them goes alone... Will they really be able to remain as just friends like this...? A story far from love~ but closer than just friendship~ Ji-eun and Min-cheol's strange school diary [Balls Friend]!