Tsuki wa Higashi ni Hi wa Nishi ni: Operation Sanctuary

Tsuki wa Higashi ni Hi wa Nishi ni: Operation Sanctuary (月は東に日は西に -Operation Sanctuary-, The Moon in the East, The Sun in the West -Operation Sanctuary-), known as Hanihani (はにはに) for short, is a Japanese adult visual novel developed by August. It was released on July 20, 2003 for Windows using the NScripter engine. The Dreamcast and PlayStation 2 versions were released by Alchemist in 2004. An anime adaptation was broadcast in Japan in 2004, and originally ran from June 30, to September 22.The title references a haiku by Yosa Buson: "Nanohana ya tsuki wa higashi ni hi wa nishi ni."

Naoki Kazumi is a boy whose parents died in an accident five years ago, and his memory went along with it. Since he had nowhere else to go, he lives with his cousin Matsuri Shibugaki and her parents. Every morning before school, he is awakened by his childhood friend, Honami Fujieda, who keeps telling him that he is not a child anymore, but still comes to wake him up. These usual, ordinary days seem to stretch on forever, until one day up on the school's rooftop, while Naoki is taking a peaceful nap, out of nowhere, a girl falls out of the sky. This girl, called Mikoto Amagasaki, comes from 100 years in the future, and she went back in time with the intention of finding her brother. When Mikoto sees Naoki, she mistakes him for her brother.