Seiko Zero

Seiko Zero (セイコーゼロ) is a light novel series that serves as a prequel to Seiko 4k: Virtual Reality. There are two known volumes, which were written by the creator of the series, Eiri Saotome.

Synopsis
The story revolves around an amnesiac girl named Aiko Kirigiri who is a noble of the Royal Capital, and the intelligent sleepyhead Former Noble Confectioner Sora Shimizu who works as Aiko's partner.

Due to the unknown cause of her amnesia, she can't remember her past, home, and even her real name. The only thing she remembered in her name was Kirigiri. Once she met Sora, Sora helped Aiko to retrieve her memories so that she can also find out what caused her amnesia.

For so long trying to find her memories back by find the mystery of the Royal District, she finally remembered that her name was Aiko Kirigiri and she has a noble title, which was the Noble Detective. Although she retrieved her memories, she's not done yet in investigating the mysteries of the Royal District with Sora.

Trivia

 * This was the last novel released in the Seiko franchise.
 * Several characters cameo in Seiko 3: Let's Go Home and Seiko 2.5: Otokonaji Rantaro to Kowareta Yasuri.