The day after the "Third Year Send-Off Party." Thanks to Sachiko's invitation, everyone decides to go to the amusement park. Without setting a meeting time, they gather freely. Sachiko is determined to arrive at the opening time with Yumi! Moreover, Kashiwagi and Yuuki are also joining them, driving in a car. The luxury car driven by Kashiwagi sets off with the four of them towards the amusement park. However, the car soon stops, and Sachiko moves to the driver's seat!! A certain past memory flashes back in Yumi's mind...!?