After learning from Ursula and the Shiny Rod that she needs to find something that she is lacking in order to unlock the fourth word, Akko joins Lotte and Sucy as they visit a magic item café owned by Lotte's parents at a remote town in Finland. The next morning, Akko, Lotte and Sucy discover that Lotte's parents have become infected with the rare Greenman Disease from eating baked hapansilakka pies made from local herring, which will gradually turn them into moss until they wither away...