Updated: December 23, 2025

Penny and Dr. Smith enter the twilight world of the looking glass when they fall into a full-length alien mirror. Behind the glass lives a care free Peter Pan like boy and a shaggy one eyed monster forever chasing him, but while Penny's mind can accept these things for what they are, Dr. Smith's can't.

Trivia:

First episode without Bill Mumy ( Will Robinson ) except in the trailer for next week's adventure; however, unlike Angela Cartwright ( Penny Robinson ) in War of the Robots ( 1966 ), Will's name is mentioned ( Twice ) as if he's somewhere around.

Goofs:

The black wire used to pull over the table outside the Jupiter-2 during the cosmic storm at the beginning of the show is visible before the table "falls" over from the wind.

Quotes:

The Boy: I thought you were something different and you're just a girl.

Connections:

Referenced in Lost in Space: The Prisoners of Space ( 1966 )