Infection is a 2004 Japanese horror film directed by Masayuki Ochiai. The film is about a run-down hospital where a doctor's mistake unwittingly creates horrific consequences for the staff at the hospital. The film was adapted from Ochiai's earlier screenplay from Tales of the Unusual. On its release, the film was part of the six-volume J-Horror Theater series.
On the film's release in Japan, it was the second highest gross film at the weekend box office, only being beaten by the film I Robot.
At a run-down, understaffed hospital, Dr. Akiba refuses to admit a patient with a strange black rash and is alerted to a serious crisis in Room 3 where a burnt victim dies, having apparently been given the wrong drug. Akiba, Dr. Uozumi, and four nurses decide to cover up the cause of death and move the body to an unused room. The head nurse then discovers that the patient that Akiba previously refused to admit has been left in the hallway and informs him.
However, when Akiba goes to check, he discovers that Doctor Akai had taken the patient and decides to study his symptoms: though he is still alive, his body mass is liquefying into green goo. Not knowing how much Akai knows about the events in Room 3, Akiba and the others reluctantly agree to help with the examination but when they return to the patient's room, they find he has vanished and the head nurse unconscious.
The head nurse awakens and begins acting strangely while she starts to bleed green goo from both her ears and eyes. The doctors realise they are at risk of infection and decide to put her on a bed and cover her with plastic in an attempt to limit the infection's spread. Soon after, the mean nurse finds the young nurse drawing blood on herself. Their conversation goes awry, when the young nurse lets out a maniacal laughs and plunges two needles into her body, splattering the mean nurse with green goo.
While speaking with a patient he killed earlier, Uozumi is overcome with emotional guilt. Akiba walks in, but finds Uozumi alone. His eyes turn white and green goo starts seeping from him. Akiba panics and turns to find the mean nurse, now infected and covered in green goo, smiling and hanging upside down from the ceiling. After finding the nurse giving her own blood to the dead burn patient and running into the infected head nurse, Akiba flees the room.
Akiba confronts Akai and accuses him of creating and spreading the virus. Akai denies this and explains that the infection is actually spread mentally, infecting the subconscious of its victims. He then urges Akiba to remember what really happened in Room 3 earlier in the night. Dr. Nakazono walks in to find Akiba talking to himself, forcing him to realize that he's been speaking with his reflection. He looks around and sees the corpses of the two nurses who are dead and covered in blood with no green goo in sight. Soon, Dr. Nakazono realizes that the last few hours have all been a hallucination. Nakazono calls the police, as Akiba recalls the events in Room 3 and realizes that "Akai" was actually the burn patient. The same series of events is shown again, but with Akiba as the burn patient and Akai as Akiba, giving the order for the wrong drug, which massacres the entire staff.
The hospital is evacuated the next morning as all of the staff, except Nakazono, are dead and the police are searching for Akiba who has disappeared. When Nakazono leaves the hospital, she sees all the red lights change to green and vice versa; panicking, she accidentally cuts her hand and green blood pours out. A shot of a locker is seen in the room where the burn victim was kept. Someone inside the locker is calling for help as green goo starts pouring out of it. The top of the locker opens and Akiba's hand covered in goo reaches out before falling to the floor.