醫學所謂的關鍵時刻在犯罪調查中稱為「黃金48小時」，這是每個警探都知道的事。在48小時內若未獲得重要線索，找出嫌犯或將之逮捕歸案，破案的機率將會腰斬成半。在長達一小時的節目中，可以看到兇殺組中的精選警探，在這48小時內和時間賽跑的調查過程。
In medicine, they call it the 'critical hour', in criminal investigations, they call it The First 48 hours. Ask any detective - they will tell you that if they don't have a lead, a suspect or an arrest within 48 hours, their chances of solving the case are cut in half. In a visual style that feels more like a TV drama than a verite reality show, The First 48 follows homicide detectives during these initial critical hours as they race against time to solve their cases. The hour-long program follows various detectives of a few select homicide teams as they track breaking cases - each with a running clock that builds pace as the 48 hours inexorably expires.
