Kaito wakes to find himself in a strange room, with no memories, and a taciturn girl named Yonagi by his side. Upon learning of his role, he immerses himself into three wondrous dream worlds with her. When all three stories meet a bitter end, Kaito recovers his memories, and the true story unfolds.
The developers utilize a unique anthology format, dividing the story into three self-contained "Cases" set in different time periods. These individually compelling narratives seamlessly converge into a fourth, overarching story that reveals the true nature of the world and the connections between the preceding tales. Players praise how this structure allows the game to explore a variety of emotional themes and romantic relationships without feeling disjointed.
The game's cast of protagonists are widely celebrated for their depth and complexity. Reviewers highlight how characters like Rin Hatano and Olivia Berry undergo genuine arcs, their motivations and flaws making them feel lifelike and compelling. The central heroine, Yonagi, is a particular standout, her growth and development central to the narrative's emotional impact.
The game tackles mature concepts like longing, hope, and the nature of love in a nuanced, subversive manner, eschewing typical visual novel tropes. Reviewers appreciate how the story progresses at a focused, emotionally-driven pace, building towards the revelatory Case 0 without extraneous filler.
The game's refined art style, featuring detailed character sprites and vivid background illustrations, is widely lauded. Reviewers highlight the effective use of the titular "cyanotype" blue in establishing mood. The emotive, atmospheric soundtrack is also praised for complementing the cinematic storytelling.