You see the danger and let your weapon serve as warning to your comrade.

At-Will   ✦     Augmentable, Psionic, Weapon
Standard Action      Melee weapon

Target: One creature

Primary Attack: Charisma vs. AC

Hit: 1[W] + Charisma modifier damage. When the target attacks you or an ally adjacent to you during its next turn, you can make the following secondary attack against it as an immediate interrupt.

  Secondary Attack: Charisma vs. Will

  Hit: The target takes a penalty to its attack roll equal to your Wisdom modifier.

Augment 1

  Hit: As above, but you can make the secondary attack only if the target attacks your or the ally's Will. You gain a bonus to the secondary attack roll equal to your Wisdom modifier.

Augment 2

  Hit: 2[W] + Charisma modifier damage. When the target attacks you or an ally you can see during its next turn, you can make the following secondary attack against it as an immediate interrupt, with a bonus to the secondary attack roll equal to your Wisdom modifier.

Published in Player's Handbook 3, page(s) 27.