The Edo-era inventor Kiteretsusai was experimenting with a prototype time machine when something went wrong—and a herd of Jurassic dinosaurs materialized in the streets of Edo. Kiteretsusai built a giant robot to capture the creatures, only to have it immediately kidnapped by a mysterious faction calling themselves the Black Ship Alien Army. Now it falls to Korosuke to rescue Kiteretsusai and deal with the rampaging dinosaurs before Edo is destroyed.