Jim . K
Lunatic Calm wrote:
Although you do control the card while it is in your hand, the abilities on cards are not active while in out of play areas, which your hand is.
See Rules Reference pg 2: Abilities
So you need to pay for her as an asset and play her to the table, where she takes up an ally slot, just like any other ally basically.
Once played, you can then benefit from her abilities, as well as the extra damage and horror she can receive on your behalf.