The triplets meet Sarang and Yuto once again! Song Ilkook prepares and visits a etiquette school for the children. A fierce teacher appears in front of the triplets and Yuto and Sarang. His words make the kids learn the "Thousand Character Classic!" Seoeon and Seojun and Hwijae go to a mud festival to escape from summer! Unfortunately, the twins only stick to their dad and don’t have fun. Will they be able to enjoy the festival? Jion and Taewoong and the Opo’s 5 sibling’s third Jindo dog, Namu, escape from the city and go to a pet pension to enjoy a cool swim. Will the Uhm family and Namu swim happily? Donggook, Seola, Sua and the youngest child, Daebak, visit the second child, Jaea, at the tennis court. However, during the tennis practice, Jaea breaks into tears and Donggook puts on a serious face. What has happened? (Source: Wikipedia)