The point of the deck is to have your opponent draw mulligan cards at the beginning, and once they catch on what you are trying to do, they will stop (as it is not required to draw the cards, it is optional). Once the game starts, you get Mewtwo out and once you attach 2 energy to it, you start blocking attacks. Every turn, you will draw an energy, attach it to Mewtwo, then discard it, to keep the block going. You continue until your opponent decks out.