The premise of the show is that girls who play the TCG WIXOSS (and only girls, because boys are gross) will rarely pull a card that contains a sentient kawaii sprite creature thing called an LRIG. Possessing an LRIG turns the girl into a Selector, which means she's forcibly entered into a competition against all other Selectors with the victor becoming the Eternal Girl who can have any single wish granted. If a Selector loses three battles against another Selector, they cease to be a Selector and are out of the competition.
Ruko, the protagonist, becomes a Selector, but she's unique among Selectors because she has no wish. I FEEL LIKE THIS WAS THE DEFINING CHARACTERISTIC OF A CERTAIN FAMOUS PROTAGONIST. HUH. Her friend Yuzuki is also a Selector and wants to fuck her brother. They both befriend Hitoe, a shy girl whose wish is simply to make friends.
By episode five, Hitoe is happy. She says that her wish has already been granted without becoming the Eternal Girl because she befriended Ruko and Yuzuki. She had already lost two battles against Selectors, meaning she was only one loss away from elimination from the competition, but she doesn't really care because she doesn't need magic for her wish to be granted now. Hitoe's LRIG expresses vague concern at the beginning of the episode, telling Hitoe to get rid of her because "something bad will happen". No further explanation is provided. Later that day, Hitoe, Ruko, and Yuzuki agree to meet up for a WIXOSS tournament against non-Selectors. Ruko and Yuzuki are held up, and Hitoe waits alone.
Suddenly, Hitoe is ambushed by a mysterious figure and forced into a game of WIXOSS. She loses and ceases to be a Selector. Because she's vanished from the meeting spot, Ruko and Yuzuki begin to search around the neighborhood for her, finally finding her stumbling out of a tunnel with an empty expression. When they address her, she doesn't recognize them. When they touch her, it causes her physical pain.
Of course, Ruko and Yuzuki both immediately ask their LRIGs just what the fuck is going on here. The answer? "Oh, BY THE WAY. We neglected to tell you because LOL IDK, but IF YOU LOSE THREE TIMES, NOT ONLY ARE YOU NO LONGER A SELECTOR, YOUR WISH IS ANTI-GRANTED. You're not merely ineligible for your wish to be granted, but THE OPPOSITE OF YOUR WISH BECOMES REALITY. FOREVER. But it was just SOOOOOOOO HARD to tell you."
Examples are provided: if you wish to be rich and lose, you'll be poor for the rest of your life. If you wish to be able to play the piano, you'll lose your fingers. Because Hitoe's wish was to make friends, she'll never have another friend for the rest of her life, and if anyone tries to befriend her, she's automatically repulsed by pain. ahahahahahaha. Character who's happy that she won't be alone anymore only to be immediately taken out? NOPE, DOESN'T RING ANY BELLS.
So now, Yuzuki's brother will *gasp* never want to fuck her if she loses. Ruko actually tries to do what it took Meguca the whole series to do and declares that her wish is to undo the curse on Hitoe, but her LRIG immediately informs her that you can't do that because reasons.
Oh yeah, and there are two bitchy psycho fashion models named Akira and Iona who are incredibly strong players and Akira has had this weird sadistic stalker complex toward all of the protagonists and wants to defeat and humiliate them all because who knows.
