You can target any number of face-down cards you control; add "Ashtra" cards from your Deck to your hand, except Field Spells, each with a different name, equal to the number of those face-down cards, then send those face-down cards to the GY. If you control an "Ashtra" monster and a face-down card, and either player Sets a card: You can target 1 card on the field; return it to the hand. You can only use each effect of "Ashtrashen - Gate to the Worlds Beyond" once per turn.