Quicksilver Dagger

Once per Turn Action -

: Attack

If another weapon's attack you control has gained go again this turn, this card's attacks get go again.

Rulings

From the Dynasty release notes

Giving a weapon attack go again essentially gives the weapon go again and meets the condition for this effect.
Quicksilver Dagger does not have base go again. It is gained by meeting a condition.

Keyword notes

Go again - Go again allows multiple actions to be played in a turn when usually playing an action with use up your action point, and therefore end your turn. A card with go again gives the controller of that card or activated ability 1 action point when it resolves.

When an action with go again resolves, its controller gains 1 action point.
Multiple instances of go again on the same card or activated ability do not stack. If a card or activated ability has multiple instances of go again when it resolves its controller gains 1 action point only.
If an action with go again does not resolve, its controller does not gain 1 action point.
You cannot reveal a card with no to Belittle. The card must have a value to its power that is 3 or less. (0 is a value)