Selbert kidnaps Myrna, Mrs. DePool's granddaughter, and imprisons her in the basement cistern. Mrs. DePool then shoots Selbert, though not fatally, and rigs a poisoned doorbell to get Tracy. Unfortunately, Myrna's fiancé is the one who rings the bell and gets the poison. Selbert clubs Tracy when he comes to investigate and he is tossed in the cistern. Mrs. DePool and Selbert prepare to leave, but Selbert presses Mrs. DePool's hand on the poisoned doorbell, grabs a chest of cash, and flees after setting the house on fire. Selbert tries to escape by hiding in the top of a parade float, but is killed when the drivers of the float intentionally drive it under a viaduct that is too low for the float.; Tracy is on the trail of Krome, an assassin who uses modified children's toys to kill his victims.; Krome's girlfriend Kitty rescues him from Tracy, but plans to turn him in to the police. At their apartment, Krome gets the upper hand and puts Kitty in a death trap. He then goes on the run in a snowstorm, followed by Tracy.; Krome makes his way through the blizzard to a doctor's office, where his arm has to be amputated because of gangrene from a bullet wound. Tracy and Patton eventually make it to the same doctor, who has sent Krome on a snowplow back to the city. Tracy and Patton pursue the snowplow. Krome forces the snowplow driver to drive out on the river ice, which gives way and the snowplow plunges through the ice.; Tracy and Patton rescue the snowplow driver, but Krome freezes to death hiding in a snow drift. Meanwhile the doctor who amputated Krome's arm bribes a constable to help to him escape, but Tracy and Patton return in time to arrest the pair. Back in the city a brute named Selbert escapes from an insane asylum and kills wealthy Angus DePool.; Mrs. DePool hides Selbert in a cistern in the basement of her mansion. Her dead husband framed Selbert, his nephew, and got him sentenced to 22 years in an insane asylum. Mrs. DePool's granddaughter suspects there is someone in the house, as does Tracy.