Perilous Voyage

• WOTC Official Reminder Textofficial rules
  Scry — Look at the top N cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.

• WWizards of the Coast2017-09-29
  Official Ruling
  If a permanent has in its mana cost, X is considered to be 0.
• WWizards of the Coast2017-09-29
  Official Ruling
  If the target permanent is an illegal target by the time Perilous Voyage resolves, the entire spell doesn't resolve. You won't scry.
• WWizards of the Coast2017-09-29
  Official Ruling
  Use the permanent's mana value as it existed on the battlefield to determine whether you scry.
• 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