Mental Apparition Disorder
The episode begins with an unmarried couple going about a secret meeting; when the telephone rings and she answers while her friend goes on up to bed, meaning for her to follow shortly. When she fails to follow, he comes back down to ask what's going on. So she stabs him.
This episode is suspiciously similar to A Disturbing Case, but it's different enough to be entertaining in it's own right, so I'll say no more about it.
This is the first episode that features Wyvern. It's also in this episode that Jeannie starts officially working with Jeff.