"Tsuki wa Higashi ni Hi wa Nishi ni - Operation Sanctuary" is a 12-episode anime series based on a visual novel by Princess Soft. The narrative centers on Naoto Aizawa, a high school student who suffers from amnesia following a mysterious accident. Unable to recall his past, Naoto returns to his hometown, where he encounters a group of individuals who claim to know him, including childhood friends and acquaintances. As he reconnects with them, fragments of his memory begin to resurface, revealing a complex web of relationships and unresolved emotions.

The story intertwines Naoto's journey of self-discovery with the lives of four key female characters: Saya Aizawa, his younger sister; Runa Kagami, a cheerful and energetic classmate; Yuuko Amamiya, a reserved and introverted girl; and Natsuki Asakura, a childhood friend with a strong sense of responsibility. Each character has a unique connection to Naoto's past, and their interactions with him gradually uncover the truth behind his amnesia and the accident that caused it.

A significant subplot involves the concept of "Operation Sanctuary," a mysterious project tied to Naoto's past. This project, which involves time travel and alternate realities, becomes a focal point as Naoto delves deeper into his memories. The series explores themes of identity, love, and the consequences of altering the past, blending elements of romance, science fiction, and drama.

As Naoto pieces together his fragmented memories, he must confront difficult choices that could impact not only his own future but also the lives of those around him. The narrative builds toward a climactic resolution that ties together the emotional and sci-fi elements, ultimately addressing the central mystery of Naoto's amnesia and the true purpose of Operation Sanctuary. The series balances its character-driven drama with moments of lightheartedness, creating a multifaceted story that appeals to fans of both romance and speculative fiction.