Continuing Rainfall Sakura (FS/S77-E026 U) Fate/stay night [Heaven’s Feel] Vol.2 Card details

[AUTO] When this card is placed on the stage from your hand, you may choose 1 "Duplicate Key to the Emiya Household" in your waiting room, and put it face up underneath this card as a marker.
[AUTO] [(1) Put 1 marker underneath this card into your waiting room] At the beginning of your opponent's attack phase, you may pay the cost. If you do, move this card to an open position of your back stage.
[AUTO] At the beginning of your draw phase, if you do not have another character in your center stage, this card gets +4000 power until end of turn.