What is the main conflict in The Cat Who Went Underground by Lilian Jackson Braun?

"The Cat Who Went Underground" by Lillian Braun is a murder mystery in which Qwill investigates the disappearances and deaths of five carpenters in Mooseville. Qwill decides to spend the summer in Mooseville at the Klingenschoen cabin. Immediately, things begin to go wrong. He is continually forced to utilize the Glinko Network for repairs on the cabin. When he decides to build an addition, he hires Clem Cottle but the industrious young man disappears. Qwill replaces his carpenter with Iggy who is lazy but Iggy also disappears. After Koko uncovers Iggy's body in the crawl space beneath the cabin, people begin to suspect Qwill of the murder.