code_18 is a sci-fi visual novel and a first game in the Infinity series , not developed by KID. The player takes on the role of Hayato, a high-school student at Ryuusei Academy in Tokyo. As part of school's science team, he invented a device that should allow him to fly and reach for the skies. However, just as he was about to test it, he notices a girl falling from the sky, carrying the same kind of device. He tries to save her, but dies trying. Time then resets to the day he was about to test his flying device.
The game's time loop mechanism is quite unique - every time Hayato reaches a certain date, he skips back through time to the same day, but without any memories of the events that have transpired. He has no idea who or what is causing the loop, nor does he know what he is doing in it. The gameplay is primarily focused on reading through the story with limited interaction, apart from occasional choices that the player must make.