Elizabeth Rogers

The Enterprise encounters a vast mechanical monster in space, which is set on a path of destruction so that whole worlds are threatened.

The Enterprise is host to some unruly guests, space hippies in search of planetary paradise. Kirk has trouble maintaining order amongst the visitors, but Mr Spock seems strangely sympathetic towards them.

Darrin becomes very romantic when a ghost takes over his body.

Mary Ellen learns about math, science and humanity as she works with a public-health nurse while preparing to enter nursing school.