The Fandom Post is reporting that Pluto TV has added the Yamibo – Darkness, the Hat, and the Travelers of the Books anime to its service. The series has been added in full, and the episodes are available with Japanese audio and English subtitles.
The series is described as:
Hazuki is a high-school student living with Hatsumi, and the two are so close they are like sisters. When Hatsumi disappears, Hazuki moves heaven and earth to find her, entering strange exotic worlds.
Yuji Yamaguchi directed the series at Studio DEEN and Tomomi Mochizuki handled the series composition.
The 13-episode series originally aired in 2003.
Source: The Fandom Post