Mastermind's Acquisition — ruling 1

In a casual game, a card you choose from outside the game comes from your personal collection. In a tournament event, a card you choose from outside the game must come from your sideboard. You may look at your sideboard at any time.

Mastermind's Acquisition — ruling 2

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.

Mastermind's Acquisition : règles, fonctionnement et interactions (MTG)

Mastermind's Acquisition is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Choose one — • Search your library for a card, put it into your hand, then shuffle. • Put a card you own from outside the game into your hand.

How it works : Mastermind's Acquisition

Original English text — Wizards of the Coast / Scryfall

#1January 19, 2018· Wizards of the Coast
In a casual game, a card you choose from outside the game comes from your personal collection. In a tournament event, a card you choose from outside the game must come from your sideboard. You may look at your sideboard at any time.
No other card is named in this ruling.
#2January 19, 2018· Wizards of the Coast
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.
No other card is named in this ruling.