After waking up from a strange dream of a girl confessing to him, Sakurai Yoshiyuki realizes he is late. After nearly running over his sister, Yoshiyuki finally makes it to school. During this time a cultural festival is starting at the school and Yoshiyuki and his friends, including his childhood friend Tsukishima Koko, decide to walk around together. Unknown to Yoshiyuki, his dream may actually become reality.
When Suginami is telling everyone about the mysterious places of the school, Sakurai inadvertently mentions the hidden stairs in the principles office. Surprised, Suginami drags Sakurai to the principles office to find the stairs. After going down them, they find a girl in a capsule. Sakurai accidently presses a red button setting off an alarm and waking the girl. Who is this mysterious girl?
An OVA bundled with a PSP game Da Capo: D.C. I & II P.S.P.