The game is afoot. -- When SH said it, [the game] was the Perp?

HenHanna <[email protected]> Fri, 21 Jun 2024 16:28:23 -0700
Newsgroups sci.lang,alt.usage.english,rec.puzzles,alt.fan.holmes
Organization A noiseless patient Spider
Message-ID <[email protected]> 
The game is afoot.

              When SH said it, [the game] was the Perp?


WHY, then, today we often think of it as:

            [The fun match has started] ?

  [The Game] as   a board-game, a friendly match....
               (a competition, a fun activity)
                             something  to be played?

Did the meaning of the [game] change?