Chain Reaction (Yellow)

“When this defends” is an event-based trigger that triggers when Chain Reaction resolves on the stack and becomes a defending card (i..e defends the attack) against an attack with go again. Whether the attack has go again is checked at the time this resolves and becomes a defending card (i.e. defends the attack). If the trigger condition is met only after this resolves, then this does not trigger.

When Chain Reaction’s triggered effect resolves, you may turn a non-attack action card in your arsenal face-up. If you do, you may play it this turn as though it were an instant.

Turning a card face-up is not considered revealing the card or putting the card face-up in arsenal. It is simply changing its state from face-down to face-up.

An action card played as though it were an instant does not cost an action point and can be played whenever the player has priority, otherwise it is still considered to be an action card.