The film depicts the process of employees from the road view service company 'Onroad Media' embarking on a new road view shoot to investigate strange phenomena occurring at the reservoir 'Salmokji.' As rumors and strange shapes were discovered in the existing road view, the company quickly decided to conduct on-site filming.

The filming team was organized around PD Su-in, and after arriving at the reservoir, the missing senior PD Gyosik (Kim Jun-han) unexpectedly appeared. Su-in sensed a different atmosphere from Gyosik than before. Subsequently, strange incidents occurred one after another among the team members, and colleague Gitae (Lee Jong-won) joined the site late, experiencing the peculiar atmosphere of Salmokji.

The exploration of Salmokji was led by Kyung-tae (Kim Young-sung) and Kyung-joon (Oh Dong-min). Kyung-tae recorded the surrounding scenery using a 360-degree camera, while Kyung-joon, who boasted of being a former Navy Special Salvage Unit (SSU) member, undertook underwater investigations. The two tried to confront the curse of Salmokji, and unidentified objects were captured on camera. Su-in's junior Seong-bin (Yoon Jae-chan) and horror YouTube channel operator Se-jung (Jang Da-ah) also investigated Salmokji using various equipment. They used devices such as a ghost box and motion detector to search for traces of invisible entities.

Su-in judged that Gyosik's disappearance was related to the reservoir and tried to uncover the truth of the incident. As time passed, the team members realized they could not grasp Salmokji and its ambiguous shapes. The film portrayed characters repeatedly wandering the same space where the boundary between water and land was unclear. The setting, where touching the water meant danger, pressured the characters.

The work expressed the water ghost's appearance in various forms, such as floating on the surface like a corpse or resembling a siren. It revealed its presence through sounds crossing underwater or by showing only parts of its body. The characters showed both fear of the water ghost's identity and a desire to confirm it.

Director Lee Sang-min stated, "I prefer the tension created by settings where mistakes must be hidden, as in ." is a story that starts from Su-in's guilt over harming a colleague and depicts characters with different personalities and fears facing an intangible horror.

The film used equipment such as a 360-degree camera and moving detector to present evidence of entities invisible to the naked eye and varied the image of the water ghost. Additionally, it was the first Korean feature film to apply the four-sided ScreenX format, showcasing a screening method that includes the theater's left and right walls and ceiling. Director Lee Sang-min said, "Because is a work that values immersion and experience in the atmosphere of the reservoir, creating a sense of space was important, so we considered the ScreenX format screening from the initial planning stage."