Rikis Bewusstsein versinkt tiefer und tiefer in der Dunkelheit. Während die verzweifelte Situation um ihn herum anhält, wird Riki von seiner eigenen Machtlosigkeit gequält. Sich fragend, warum er so geworden ist, beschließt er, gegen die Realität anzukämpfen und seine eigene Schwäche zu überwinden – um die wahre Bedeutung hinter dem "Geheimnis dieser Welt" kennenzulernen, um einen Wunsch zu erfüllen, um eine Zukunft des Lachens zurückzubringen...
Having another attack of narcolepsy, Riki realizes that he always falls asleep at the sight of unpleasant situations, since he saw his parents' dead bodies in a car accident when he was a child, and determined to overcome this weakness, he awakens with Rin's help. Knowing that the bus will explode, Riki and Rin start rescuing the other students from the wreckage only to discover that Kyousuke is using his own body to prevent the gas from leaking further, leaving the duo no other option but to pick him up after carrying all the others to safety. The bus explodes just after Riki and Rin return to rescue Kyousuke, but the incident ends with no deaths. Three months later, all of the students have returned from the hospital except Kyousuke, who is still in a coma, and the other Little Busters spend their days together, waiting for him to return. Once Kyousuke finally returns, the Little Busters have their own, private field trip to the beach together.
深く、どこまでも深く――。
理樹の意識は暗い闇へと沈んでいった。
壮絶な事態が進行する中で、理樹は何もすることができない無力感に苛まれた。
―なぜこんなことになってしまったのだろう―理樹は自問自答し、自分の弱さを乗り越えるために現実に抗うことを決意する。
「この世界の秘密」の真意、願いに応えるために、未来を笑顔に変えるために──。
친구들을 구하기로 결심한 그 순간, 리키에게 또다시 기면증이 찾아온다. 쿄스케가 자신의 모든 것을 걸고 리키에게 가르쳐주려고 했던 것. 그것을 떠올리며 리키는 자신의 과거와 맞서기 시작한다.
情況危急中，理樹卻再度陷入昏睡。潛意識中的理樹努力克服自己的軟弱，對抗現實中的難關。一切都是為了Little Busters的未來…
