I'm with you completely, Robert.  I'm convinced that Christopher Plummer must have woken up one day and screamed, "Shut up!  Shut up!!" before they divorced.  She's a talented actress, but not the most compelling actress.  Her best work here, I believe, is the "Nefertiti" multi-part saga, and that's because she had great chemistry with Russell Horton.  She worked well with Lloyd Battista, too.  But whenever she starts screaming, wailing (as in "Sleepwalker"), cackling, or arguing loudly, I lunge for the volume control.