A detective finds himself in a predicament to find the cause behind recent similar deaths.

A bridge accident that took place a week ago is talked about in the news. The detective is chasing a mere thief and proceeds to catch him.

The detective meets up with the cop and asks him to find him a better job. He turns down the offer to investigate a suicide and then accompanies the cop to look into the matter of another dead body found in a car. The detective examines the body for any clue as to find the cause of death but is told that the victim died in a hotel room around 3pm due to suffocating. The detective asks for the forensic report of the food found on victim's clothes.

The detective is summoned by the cop to look into another death caused by suffocating that took place around 3pm too. The detective asks for another report of the food plate found in the second victim's room. He delves further into his mind to find the connection between the deaths and the reason for 3pm and suffocation.

The forensic report then states that the cause of death isn't the food. The detective is on his laptop and comes across details of four people who worked on the project of bridge construction 10 years ago. He deduces that out of the four people, two are already dead and one face looks familiar to him. He calls up the cop to ask him for the forensic report of the suicide he mentioned earlier. The time of death states 3pm.

The detective goes to the mortuary to further investigate the belongings of the suicide victim. He sniffs the clothes and tenses up as all the deaths now make sense to him. He finds out the details of the fourth and last victim and makes an attempt to save him before it turns 2pm. The detective catches the killer in the hotel room with the final victim and rescues him in time.

He explains it to the cop about how the killing was done with a perfume that only affects the victim after one hour, which is why the reports mentioned the cause as suffocation. The motive for murder was the bridge accident that the killer's parents were involved in, with the four victims as the main people responsible for the construction of the bridge.