EX is a hidden, unlockable what-if scenario only available after the completion of Doomsday Dreams. To discover it, you must click EXTRA on the main menu, then click Leave. This will trigger a choice where Mamiya Yumehisa can pick up a burnt what-if page while searching for Natsume. After choosing to pick it up, go back to the RESTART screen and click the new arrow on the right side of the screen.
