“Day of the Killer, Night of the Fool” is a continuation of the storyline from Man-Thing #2 “Nowhere to Go But Down.” The splash page opens with the Man-Thing brooding in the distance while a crew from F. A. Schist’s Construction Company points at a small shack deep in the Florida Everglades. This shack served as a failed death trap to destroy the Man-Thing. Mr. Schist and Professor Wilbur Wickham recall the failed attempt and blame it on heavy chain that the targeted swamp creature had in his possession when the death trap was sprung. F. A. Schist has been trying to rid the swamp of the Man-Thing since Adventure Into Fear #16 so he can drain this section of the and build a profitable parking lot and airport.
Unnoticed, the Man-Thing moves silently toward the group, remembering his pain of the electric shocks in the little metal shack, remembering the savage anger and the anguish. He wants to destroy the shack he associates with the terrible pain he endured. Startled, the construction workers attack the Man-Thing by swinging tools and axes at him. Their weapons are powerless against him as they merely ooze through his hulking body.
Standing in front of the shack are Mr. Schist and Professor Wickham. Both men are objects of his loathing. In route to the shack the Man-Thing picks up both men and tosses them into the swamp. Undaunted, he trudges to the shack and tears it apart. Piece by piece the Man-Thing rips the steel panels of the shack and hurls them into the murky water. The workmen rescue Schist and Wickham and leave the swamp returning to the construction camp.
Less than a mile from this scene of revenge, a farewell is taking place. Richard Rory and Ruth Hart are saying goodbye to a group of bikers known as “the Skull-Crushers.” In Man-Thing #2 they were involved in a deadly battle, led by a thieving bandit called Snake, who tricked the bikers into believing that Ruth had stolen their money. Richard helped them recover their money and set them back on their way to . Richard and Ruth are determined to start a new life together. All they need is some gas for Richard’s VW Bus and a little luck.
As the bikers motor their way down the highway, now headed for instead of , a strange human figure stands firmly in the middle of the road ahead of them. This figure is the Foolkiller. With the motorcycles almost upon him the Foolkiller pulls a gun and fires a silent bright light burst at the riders knocking them off their bikes. The menacing figure approaches one of the riders named “French” and demands to know the whereabouts of Richard Rory. When French responds with a snide remark, he is shot and destroyed by the Foolkiller. Turning to another rider, the man with the powerful weapon asks the same question. This man, too, is shot into oblivion and the Foolkiller walks to his waiting vehicle to continue his search Richard Rory.
The scene shifts again to the F. A. Schist Construction Company Camp. Mr. Schist and Professor Wickham are just arriving from their encounter with the Man-Thing. Also arriving at the camp is the Foolkiller who overhears Schist talking about killing the Man-Thing. The Foolkiller assures him that he wants to kill him too, and that it would also be Mr. Schist’s last day on earth. Schist is handed a card by the Foolkiller which reads: “FOOLKILLER, ~ unum~ You have 24 hours to live. Use them to repent—or be forever damned to the pits of Hell, where goeth all fools. Today is the last day of the rest of your life, use it wisely—or die a fool!” Schist is not amused and his construction workers move in to assault the mysterious man. Lifting his weapon, the Foolkiller annihilates those who were after him, sending them to their doom.
In another location, Richard Rory and Ruth Hart are joined by a lost motorist who is looking for directions. Richard explains his need for fuel and the motorist gives him two gallons of gas and continues on his way to an unnamed country club.
As evening falls on the , the Foolkiller is pursuing a third victim of the day: Theodore Sallis, also known as the Man-Thing. In the Foolkiller’s mind, Ted Sallis is guilty of “playing God” by creating a serum that would help mankind win the war over pollution. His attention is diverted by a speeding helicopter overhead. Thinking it is Mr. Schist trying to escape, the Foolkiller shoots the copter down with this gun. The helicopter, however was carrying flood victims to safety, not Mr. F. A. Schist. The fallen copter awakens the Man-Thing and he wades over to the crash site to investigate.
The victims survive the crash but are immediately attacked by a swarm of alligators. The Man-Things intervenes by placing himself between the gators and the crash victims. As the retiles begin their attack, the Man-Thing single-handedly defeats them, sending them flying through the swamp.
On the shore the Foolkiller reassesses his mission to kill Ted Sallis. Confused whether he is mistaken or not, the Foolkiller decides to let the Man-Thing live. However, the swamp dweller does not understand the mysterious man’s words and continues to come toward him. The Foolkiller raises his gun and shoots the Man-Thing with a mighty blast. The white heat from the weapon staggers the swamp creature, as he totters to and fro. And finally, when his insides are “as dry as chalk,” the Man-Things falls to the ground, presumed dead. Has the Foolkiller ended the life of Ted Sallis, turned into a pitiable swamp creature? And what about Mr. Schist’s 24 hours to live? Will the Foolkiller continue to stalk Richard Rory? The answers will be forthcoming in the next issue of Man-Thing!