True Targeting

Momentum power
Interrupt action OR free action on your turn; you must spend your momentum
An invisible or otherwise hidden enemy attacks you, or you try to attack an invisible or hidden enemy.

The attacker's invisibility isn't going to work on you. It might work against your allies, but you see through it and can tell where the creature is well enough to target it normally or be aware of its imminent attack.

Epic Feat: 

If the enemy's attack misses, you regain momentum.