[s3e18] The Move -

How the characters "move" from their winter personas into their spring selves.

Often discussed as the final "move" of Special Agent Dale Cooper as he attempts to save Laura Palmer, leading to the haunting "What year is this?" ending. Reddit Community Discussion . [S3E18] The Move

If you are referring to a different series or a podcast, here are other notable "S3E18" entries that involve "moves" or significant shifts: How the characters "move" from their winter personas