Viva la Vida
Whenever you roll a 10 on a die, you get to roll it again. Your 10 still counts as a success, but you get to roll that die over—sort of like getting an extra die in your dice pool. This is really nice if you keep rolling 10 on the same die.
For example, say I roll 6 dice:
1 4 9 10 5 7
I currently have two successes because of the 9 and the 10. I get to reroll the 10, because of the 10 Again rule.
So I roll it again and I get another 10. I now have three successes, and I get to roll it again.
Okay, so now I have four successes and I don’t get to roll again since it’s not another 10.
In certain circumstances, different Seemings get to reroll 9s and even 8s, as per the 10 Again rule, and still benefit from rerolling 10s. If someone who had an 8 Again on a certain roll rolled three 8s and a 10, they would get to reroll all four of their successes. If they rolled a 9, though, they wouldn’t get to reroll that.
Additionally, some Seemings don’t get 10 Again on certain rolls. Be sure to check your Seeming Blessing and Curse for this information.