The ghouls of Anteiku invaded the Aogiri's site in order to rescue Ken Kaneki who is being tortured. Due to provocation, he unleashed greater power enough to defeat Yamori. To become stronger, he decided to join Aogiri and left Anteiku. Ghoul investigators also making their moves by collecting information about the eye-patched ghoul - Ken Kaneki.

作品以日本著名推理小说家江户川乱步的诸多名作为原案，将乱步的幻想世界观与现代的舞台相结合。动画讲述在某所中学发生了教师被杀事件。就读于这所学校的少年小林，与前来搜查事件的天才侦探明智相遇。对于只搜查异常犯罪的明智感兴趣的小林，不顾朋友羽柴的反对，自愿成为其“助手”。在接连发生的奇怪事件当中，小林很快和明智展开了调查。