Author's note

They say that a single flapping of a butterfly's wings can cause a tornado on the other side of the Earth. That's the butterfly effect. And if that's true, then everything is possible.

* * *

On the one hand, BTS are about to finish promoting their latest album. To their great surprise, Bang PD has come up with a completely crazy idea.

On the other hand, four young girls are finally realising their childhood project: to live together in Seoul.
Jin Ah and Yoo Jin are opening a café in Myeong-Dong, Bo Hwa is desperately looking for a job and Mi So is trying her luck at the Hongik University of Art.

Their lives will soon be turned upside down by unexpected encounters and the hooks of the Universe.