Aspects can be invoked by the player to help the hero succeed—or invoked by the GM to lessen the hero’s chances! An Aspect can be invoked once per Action (plus any Free Invokes, earned through other actions), and will either grant a +2 bonus or a reroll of the Fate Dice.
When a player invokes an Aspect, the player pays a Fate Point to do it.
Aspects can also be compelled to make Bad Things Happen. The Bad Things are called Complications. Compelling an Aspect triggers a narrative twist: “Because of [the compelled Aspect], the [complication] happens.”
Both the players and GM can compel Aspects, but Compels don’t give bonuses—instead Compels always change the scene’s narrative in ways that complicate the hero’s story, multiplying his obstacles, widening the scope for drama and struggle, and making victory sweeter—what good roleplaying is all about.
When an Aspect is compelled on a player’s character, that player can earn a fate point.
When the GM invokes a hero’s character Aspect as a compel (ie. in opposition to the hero) the GM passes a Fate Point to the hero’s player.