Though technically the finale (spanning episodes 21 and 22), the season 4 conclusion involves a massive secret being revealed.
Entertainment Weekly provides a recap of "Mr. Kaplan: Conclusion," which centers on the "truth" Red is hiding. Other Notable S4E21 Episodes [S4E21] The Last Word
Season 4, Episode 21 is titled While not titled "The Last Word," it is famous for Captain Picard’s concluding monologue about freedom and vigilance. Though technically the finale (spanning episodes 21 and
: "Asylum" (Part 1 of the S4 finale). You can find technical and plot discussions on Wikipedia . Other Notable S4E21 Episodes Season 4, Episode 21
: "Career Day." A lighter episode involving Claire returning to the workforce, detailed on Wikipedia .
Depending on which show you are referring to, here are the most relevant "papers" or guides:
You can find a detailed review and analysis of its political relevance on Star Trek Forever or read about its iconic civil liberties speech . The West Wing