The character deck of 40 cards contains 4 copies of 10 characters. 5 of these characters are on the day team, and 5 on the night team. Each group of the same characters will give you a score depending on their team and how many times you've interacted with them (the size of the pile). The reference score card in the top-middle of the play area that shows how scores are calculated (you can flip it over by clicking on it to see the same information in a different layout that might work better for you). Obtain a score further from zero than your opponent to win the round! This will be accomplished by collecting odd numbers of characters from one team and even numbers of the other (but 4s aren't as good as 2s).
The looking glass (the main card area) can be set up 5 different ways. When you start a new round, a random setup will be chosen and 28 cards will be randomly dealt in that pattern. Of the other 12 cards, 4 will be given to each player, and 4 left out of the round unseen. Your hand is secret from the other player, but these cards will go in your score pile, so think of them as already in your score pile and consider them when calculating your path.
On your turn, select any card in the looking glass that is completely uncovered by other cards (it doesn't have to be on the same side that your score piles are). You will collect it and your opponent will collect the reflection: the card directly across from it in the same position.
You will alternate turns until the mirror is empty and then your scores will be calculated according to the reference card. The player with the highest absolute score will be declared the winner. In case of a tie, the player that went first that round wins. A win gives you the layout card as a point. You'll keep playing more rounds until a player has 3 points.