Deadline is an interactive fiction computer game published by Infocom in 1982. Written by Marc Blank, it was one of the first murder mystery interactive fiction games. Like most Infocom titles, Deadline was created using ZIL, which allowed the easy porting of the game to popular computer platforms of the time such as the Apple II and the Commodore 64. It is Infocom's third game. The player's character in Deadline is an unnamed police detective, summoned to a sprawling Connecticut estate to investigate the apparent suicide of wealthy industrialist Marshall Robner. At first, it seems a very straightforward case: the body was discovered in the library, which had been locked from the inside, and the cause of death was an overdose of his prescribed antidepressants. But something just doesn't feel right. Could someone have killed Robner for his money? Did he make an enemy through his business dealings? Or was there some other motive? With the able assistance of level-headed Sgt. Duffy, the player has twelve hours to solve the case before it is closed forever.

A wealthy industrialist, Mr. Marshall Robner, locked himself in the upstairs library of his New England colonial estate one night and committed suicide by taking a lethal overdose of anti-depressants. Or did he? You are the Chief of Detectives. You’ve been asked by Robner’s attorney to make a thorough investigation of the case, simply to “quash the suspicions which are inevitable” when a moneyed man dies a sudden and unnatural death. The Medical Examiner found nothing unusual, and interviews with family members and family associates are consistent with the idea that Robner committed suicide. Everything fits neatly—maybe too neatly. You smell foul play, and you have 12 hours to crack the case. If you arrest someone, you’d better have the three traditional ingredients to an ironclad case for the prosecution: the accused must have had a motive, a method, and ample opportunity to commit the crime. There are many possible endings to this case, and the one you reach is determined by your actions and by the deductions you draw from the evidence you gather. But one ending fits the facts better than any other, and you will know it when you reach it.