Fateful Showdown

• WWizards of the Coast2016-09-20
  Official Ruling
  If Fateful Showdown's target becomes an illegal target, you won't discard your hand or draw any cards.
• WWizards of the Coast2016-09-20
  Official Ruling
  The number of cards in your hand is counted only as Fateful Showdown resolves. Fateful Showdown is on the stack at this time, so it's not counted.
• WWizards of the Coast2018-01-19
  Official Ruling
  There are many important moments in the story, but the most crucial—called “story spotlights”—are shown on cards. These cards have the Planeswalker symbol in their text box; this symbol has no effect on gameplay. You can read more about these events in the official Magic fiction at http://www.mtgstory.com.

Rulings via Scryfall