Historical clue formulations

• Unresolved parts of a plot — 2026-02-15
• They may be tied up in a sequel — 2022-05-13
• Unresolved details ... and a hint to this puzzle's circled letters — 2022-04-18
• Things that should be tied up by the curtain? — 2014-02-23
• Unfinished business — 1994-03-19