Takasu Ryūji is going through a difficult period in his life. To make matters worse, Christmas—if we can call it that—didn’t go well at all: he managed to land in the hospital for several days with severe flu. And then Taiga stopped coming by, trying not to provoke inappropriate rumors. But now a school trip is being planned. Japanese students take trips like this to other prefectures for tourism-and-education purposes several times throughout their years of schooling. And since they’re already seniors, everyone is looking forward to the trip to Okinawa, which all of them associate with a beach, sunshine, and fun. Nobody could have imagined how everything would turn out in the end...