Ai and his childhood friends used to play together as part of the ‘World Defence Club’. But one day, it disbanded and one of the girls changed schools, so they gradually lost touch with one another.
Now the girl who had left, Hiiro, returned and their circle of friends came together once more. However, this time their club name was the ‘Shrine Gate Defence Club’. They give advice to students for relationships, even though they themselves have no experience in romance. As they participate in club activities, they started to think about falling in love too.