Step Between Worlds is a rare Sorcery card from Outlaws of Thunder Junction Promos (POTJ), collector number 70p. Current market price: $0.33 (foil $0.50), TCGplayer market prices via Scryfall.
Each player may shuffle their hand and graveyard into their library. Each player who does draws seven cards. Exile Step Between Worlds. Plot {4}{U}{U} (You may pay {4}{U}{U} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)