The Terror scales the building of his intended victim, an informant named Jurgen. Spying his quarry, the Terror crashes in through the window, and attacks Jurgen. At that moment, Jack Ryder enters Jurgen's apartment, to interview the man. The Terror attacks Ryder. The assault raises such a clamor that the Terror flees, for fear of police intervention. Ryder is able to garner the names of three men from Jurgen, as well as a cryptic reference to a woman, before Jurgen dies.
Back at the WHAM-TV station, Ryder asks to be allowed to continue the investigation into Jurgen's murder. The station manager, Bill Brane, has other ideas. The weather girl, Vera Sweet, claims to have been threatened, so Brane tasks Ryder with protecting her. Meanwhile, the Terror is busy assaulting gangland chief, "Baldy" Pate. The Terror demands half the profits of Pate's rackets, or else he'll use the evidence he's amassed against Pate to put him in prison for life. The assault on Pate prompts a meeting of the notable underworld bosses, all of whom have received similar threats from the Terror. Suspecting that one of their own is the Terror, the mob bosses uneasily depart one another's company, each with his own plan for rooting out and dealing with the Terror.
Ryder then abandons Sweet outside her door, and travels to the penthouse of the first man Jurgen named, Gerk Kreg, a notorious mob boss. Ryder transforms into the Creeper and storms Kreg's apartment. A brutal melee ensues, as the Creeper attacks a quartet of Kreg's gunsels, all while interrogating them between punches. Kreg gets the drop on the Creeper, stunning him with a blow to the head. Before Kreg murders the Creeper, he demands his men reveal the Creeper's identity. The Creeper, however, seemingly wears no disguise, and the gunsels' astonishment over that fact gives the Creeper the opportunity to break free and escape.
Ryder continues his investigation into Jurgen's death, by meeting with the final two men Jurgen spoke of with his dying breath. The private detective, Hack Axeley, has no time to answer Ryder's questions. The lawyer, Vance Cleary, though, is a bit too forceful in his protestations regarding the investigation, rousing Ryder's suspicions. Ryder transforms into the Creeper, intent on re-interviewing Cleary. However, terrified onlookers spot him scaling the wall, and summon the police, forcing Ryder to flee.
Back at the station, Brane tears into Ryder for continuing the investigation, and abandoning Sweet. Axeley has filed complaints. Cleary is threatening to file suit. Ryder walks Sweet back to his apartment, little suspecting the the Terror is en route there, too. Ryder's investigation has come a little too close for the Terror's comfort. As Ryder steps into his darkened apartment, he is ambushed by the Terror. Sweet's high pitched screaming threatens to bring the police, forcing the Terror to, once again, flee the scene. This time, though, Ryder is in hot pursuit, as the Creeper. The two adversaries battle it out across Gotham City's rain slicked rooftops. One misstep gives the Terror the upper hand. The Creeper narrowly avoids being killed twice. Recovering from the second peril gives the Terror time to escape. Commentary from the Terror, during the combat, allows The Creeper to cross off Kreg as one possible identity for the Terror.
Returning to Axeley's office, Ryder finds the detective, beaten to death, his office thoroughly ransacked. Remembering that Jurgen made reference to a woman, Ryder begins to suspect Axeley's secretary, Ida Horn, may hold the key to unmasking the Terror. Meanwhile, Kreg rounds up his men and authorizes a hit on the Terror.
Kreg's men spy the Creeper entering Horn's apartment, through the window. Despite the order to take down the Terror, Kreg's lieutenant decides to pursue the hundred-thousand dollar bounty on the Creeper instead. Confronting Horn, the Creeper begins to interrogate the, clearly, spooked secretary. A sudden movement draws the Creeper's eye to a puddle of rain water, pooling under Horn's drapes. Continuing his interrogation, the Creeper slyly palms an orange and hurls it at the figure hiding behind the curtains. It is the Terror. Once again the two men begin a frenzied battle. This time, though, Horn, joins the fight against the Creeper. Evading Horn's blows while holding his own against the Terror is no easy feat. The Creeper finally tangles Horn up in her own drapes, then tackles the Terror, as the villain exits out the window. Dangling from a cable, above the street, the two men continue to struggle. The Creeper unmasks the Terror, revealing him to be Forbes, Axeley's assistant. Down below, Kreg's men gather and prepare to fire on the Creeper and the Terror. In his desperation to escape the Creeper, the Terror races headlong into Kreg's gunsels. The Creeper intervenes, subduing the Terror, while also engaging Kreg's men in combat. In short order, the police arrive, prompting the Creeper to make his exit.
The Terror, along with Kreg's entire gang, are all taken into custody. The Creeper, as Ryder, returns to his apartment, and is greeted by a furious Sweet. Ryder has a bit of fun at Sweet's expense, but the desired result is accomplished. Sweet leaves, the echo of Ryder's laughter fading in her ear.