The Cat Who Turned On and Off is the third novel in a series of murder mystery novels by Lilian Jackson Braun.
Qwill and his two lovable Siamese, Koko and Yum Yum find themselves in a rundown section of the city known as Junktown. Expecting it to be a haven of dopers and the homeless, they are surprised to see that it is a collection of old antique stores trying to survive. They also find mystery and murder waiting for them. A mysterious fall ends the life of one of Junktown's leading citizens and Qwill suspects it was no accident. It takes Koko to prove him right.