Indigo Island is a place like no other, to deter emigration and attract tourism they have become the 'sex' destination as residents are punished if they do not have frequent sex. On this crazy island, Hitori...

One day, a weird girl with pink hair and green eyes appears in front of Nagi Tsukuba, an average high schooler. She claims to be Stra, the "Prophecies of Nostradamus" and after guessing his future and guess ...