The City on the Edge of Forever

Deductions

• television series episode is for example The City on the Edge of Forever ⇐ (The City on the Edge of Forever is a television series episode), (is a is inverse of is for example)
• The City on the Edge of Forever is a television series episode ⇐ (Star Trek episode is subclass of television series episode), (The City on the Edge of Forever is a Star Trek episode)
• Star Trek episode is for example The City on the Edge of Forever ⇐ (The City on the Edge of Forever is a Star Trek episode), (is a is inverse of is for example)