The Problem deck is a deck of exactly 10 Problem cards, at least one of which must be a Starting Problem. It can only include up to two copies of a card with the exact same name.

At the beginning of the game, players select a Starting Problem from their Problem deck to become their active Problem. During the game, whenever a Problem is solved that Problem’s owner places it on the bottom of their Problem deck and flips a new active Problem from the top of their Problem deck.

A player requires one Mane Character in addition to a draw deck (45+ cards) and a Problem deck in order to start playing the MLP CCG.