Gourmet writer and columnist Justus Walters is in his apartment working on an article when his neighbor, Elizabeth Croft, calls. He tells her to stop calling and hangs up, and then listens as she walks down the stairs from her apartment and comes to his door. She ignores his yells to stop knocking and Justus finally opens the door. Elizabeth is romantically interested in him, but Justus says that only dated her once to be neighborly, and he has no interest in her. He slams the door in her face, and Elizabeth calls through the door that someday she hopes that he'll be helpless and will need someone. As she walks away, she fakes twisting her ankle on the stairs and calls for help, but Justus immediately sees through her ruse and ignores her.
In the kitchen, Justus hears the faucet dripping and checks out the sink. A spider has climbed out of the drain and Justus looks at it in revulsions. He washes it down the drain and tries to go back to work, but hears the faucet dripping again. When Justus checks on it, he discovers that the spider has climbed back up... and it appears to have grown. He washes it down after some effort and hears the doorbell ring. It's Mr. Boucher, the landlord and handyman, who has come to fix Justus' thermostat. The writer complains about the spider, insisting he has arachnophobia, but the landlord is unimpressed. He says that Justus will just have to live with the spider because he's not going to call an exterminator in the middle of the night, and then leaves.
Justus hears a squealing noise from the bedroom and opens the door, and sees the spider inside... now the size of a large dog. It lunges at him and he hastily closes the door, and then goes to get Boucher. The landlord assumes that Justus is drunk and tells him to go away. Desperate, Justus goes upstairs to Elizabeth's apartment and suggests that she invite him in for brandy. She does so and suggests that he apologize. He does and claims that he likes her, but Elizabeth doesn't believe him, saying he doesn't even like himself. He tells her about his phobia and the fact that there's a giant spider in his bedroom, but Elizabeth says that there's no such things. Justus has no answer for her and starts to call the police, but she warns him that they'll have him locked up as a lunatic. When Justus insists that he's telling the truth, Elizabeth dismisses him as a drunk and tells him to get out.
Justus starts to go, but begs her to come with him and she agrees. They go into the apartment and she doesn't see the giant spider. Justus says that it was in the bedroom and she looks inside, and tells him that there's nothing inside. She offers to show him and leads him inside, but then slips out and locks the door behind him. As Justus begs her to let her out, he hears a squealing noise. The writer begs Elizabeth to let him out, but she throws his earlier words in his face and leaves, giggling. Justus backs against the door in horror of the approaching creature as Elizabeth leaves.