the male protagonist, hai shenhang, is an insensitive and only striving for his studies. aaa。 the story begins in the hustle and bustle tokyo. it is the day when the exam results are released. hang and his classmate and friend chanyu went to see the results, thinking that victory was taken for granted, but found that there was no number on the list! it turned out that it was because i chose the wrong answer to multiple choices. so the school failed, and the butler who had been taking care of hang also wanted to leave him! just when things were so bad, two mysterious people suddenly appeared and said that congratulations to hang for being recommended to attend a mysterious school, which was actually on a mysterious island. －－PromisedIsland...... hang was extremely reluctant, but because he had no choice, he had to set off and arrived on the island and found strange things everywhere. in addition to constantly seeing old people who looked like housekeepers appearing next to hang as different characters, the most terrifying thing is that twelve beautiful and cute girls appeared one after another, and they also considered themselves hang’s sisters! that's it. hang lives with twelve sisters of different personalities on this island, revealing the most gorgeous page of his life... at the same time, another girl named zhenshen pretends to be hang's thirteenth sister, and gets involved. WelcomeHouse zhonghe hang lives with his sisters to monitor hang's every move. she often communicates with a mysterious person with emails. their purpose is to get xiao hang back to the hopeless tokyo.