After a spate of time-wasting telephone calls, the Doctor had told Miss Frayle not to bother him with them; she must dismiss the callers and leave him to work on his thesis. But when the telephone rang again it was Professor Howard, clearly in the midst of a desperate struggle, wanting to speak to the Doctor on a matter of life and death. The Professor was being attacked - by spiders. So begins one of Doctor Morelle's strangest cases ...