For want of a nail, the shoe was lost;
For want of the shoe, the horse was lost;
For want of the horse, the rider was lost;
For want of the rider, the battle was lost;
For want of the battle, the kingdom was lost,
And all for the want of a horseshoe nail.
- Benjamin Franklin
A variant on the Butterfly Effect, this is a Time Travel Trope concerning how a minor change in the past can have vast consequences. If things spiral out of control or result in a great calamity, you're looking at the Butterfly of Doom.
For Want Of A Nail also a common element of Alternate History tales, where the world is just like ours, except for one small detail… and all the myriad ripple effects that one small change results in.
The opposite effect is In Spite Of A Nail.
Game and Story Use
- Late in a campaign, you could present some big issue that turns out to have stemmed from a seemingly trivial action or decision the players made back in the first or second session. See also Butterfly of Doom.