Riddle to iu waka no otoko wa, "Akui no Hako" to iu himitsu kikan ni yotte, nakama subete wo ushinai, sekai ga horobu shiawase no shi wo ou. Zetsubou ni tsutsumareta Riddle wa, hitori no shikou ni suki: saigo no jiko no mae no jikan ni modoru koto. Sen-nen no chikara de, Riddle wa jikan wo modosu koto ni seikou shi, "Kore wo yome ni suru!" to chikai, issho no tabi wo hajimeru. Ichinichi no chishiki to gijutsu wo motte, Great Sage Riddle wa, kako e no arata na tabi ni tsuku.