On a dirty New Orleans street at night, we saw an upstairs window open. Poker is being played in that room. One of those players is Seaman Kochak (Lewis Charles), who picks up a cauldron he just won and says he doesn't feel well and needs a break. The other players objected, Black (Jack Palance), Raymond Fitch (Zero Mostel) and Poldy (Guy Tomayan), claiming it was too early to quit. Despite threats, Kochak left. Black quickly spoke to the other two, ordering them to bring back Kochak or the money. Raymond and Poldy followed Kochak out, stopped him and pushed him off, but Kochak continued on his way. Raymond and Poldy had given up, but an angry black man demanded to follow him. Some distance away, in the quayside, Kochak was surrounded with brief fighting. Black killed Kochak with two shots and ordered Raymond and Poldy to dispose of the body after getting the money back.
On a pier by the river, Kochak's body was found and police picked it up and took it to a morgue. A post-mortem technician dug up two bullets and found the body a bit odd. He immediately isolated the body and called Dr. Reed at home. Dr. Reed reluctantly agreed to go back to the morgue and confirmed that the deceased had pneumonic plague, similar to lymphatic plague, but which struck the lungs and was not spread by rats, but by coughing, sneezing and person-to-person of physical contact transmission. He was responsible for isolating everyone who came in contact with the body, cremating it, and beginning to vaccinate police and morgue technicians.
In an emergency meeting with Mayor Murray, Police Chief Tom Warren and other authorities, Reed described the potentially dramatic consequences and death of not finding someone infected. Death occurred within 4 days of onset, while illness occurred within about 2 days of exposure to an infectious disease. So they have a 48-hour window to try to find those exposed and prevent further disease through vaccination. Since the deceased was moved by the murderer, the murderer has been exposed and must be found. The search must be carried out under a different pretext, otherwise the killer could leave town and potentially infect the entire country. This secret must also be kept secret from the public, otherwise there will be a massive exodus of people that could spread the disease over a wide area.
The mayor supported Reed, and the rest were reluctant. Warren objected that he had an impossible job because the murder victim was unidentified, but complained that he promised to do his best. Reed and Warren display a quick temper and grudging respect for each other as they begin their hunt for the killer. Warren ordered all known petty criminals and suspects to be rounded up, shown a picture of a murder victim, and asked what they knew. Reed was so nervous that he obstructed the police process, so he went to try other methods to identify the murder victim himself.
Dr. Reed walked into the seafarers hiring hall and offered a $50 reward to anyone who could identify the murder victim, but to no avail. He sensed that someone was reluctant to give information, so he announced that he would be waiting at a nearby café, Franks' place, in case anyone wanted to speak to him. After waiting for a while, a girl approached him and said she knew a boat owner who may have seen the unidentified victim. Reed followed her to a boat, the owner of which denied knowing anything. After some shoving, the owner said that he also opened a cafe, which was run by his wife, and that he would ask his wife.
