Mashiroko Lake

Mashiroko Lake (真白湖, Mashiroko mizuumi) is a large Shinyuuchi, found in inland Hokkaido and one of several targeted during the Shinyuuchi huntings. The lake is famous for the thick mist that blankets it.

Plot
A team from the Shadow Organization's Investigation Office visited the lake after learning of the sudden disappearance of the Shinyuuchi. Assisted by Rokurou Ougi, who volunteered for the task, Chief Kouzou Tanno determined that the incident had not occured naturally, and that a high-level ability user who could manipulate space was involved. It was further decided that they will need a similar ability user to repair the space, and the area is ordered sealed off for some time. Namihira volunteers to head the case, and Masamori Sumimura was brought in to repair the Shinyuuchi, though doing so only strengthened the likelihood of another Kekkaishi having been the original culprit.