As I'm trying to learn the cards, I'm seeing text like "if it's winter" or "if it's summer". What sets the seasons? I'm curious if there's a plot card that sets this or if it's something players agree upon before starting a new game or what?
Seasons questions
White Raven, Black Raven, Crown of Winter, Crown of Meereen, and Crown of Azor Ahai.
As Xenu points out, there's a couple of cards that will make it Summer or Winter, first and foremost the two Raven attachments found in the A Time for Ravens chapter pack cycle (specifically in A Song of Summer and The Winds of Winter). So far, all cards that make it Summer or Winter are attachments, and they do so as a passive constant effect. There's no rules associated with the seasons; the mechanic is entirely fueled by card effects.
Does that mean that when the crowns induce a season, the gold bonus/penalty doesn't take effect?
Exactly. The gold bonus/penalty is an effect of the Raven cards, NOT of the seasons.
What happens when two season-enabling cards are in game at the same time? For instance crown of winter and crown of meeren....
It is both Summer and Winter at the same time.
Arrdet said:
It is both Summer and Winter at the same time.
Wow, that's quite interesting. It also presents some intriguing possibilities, particularly for Baratheon, and perhaps even for Alliance type decks.
Anyone ever seen a multi-season deck?
Shenanigans said:
Anyone ever seen a multi-season deck?
For one, you can really only do it with crowns, which are unique attachments. So it's not simple to actually make it happen, then keep it going.
Second, while you would get all the benefits of both seasons, you'd get all the drawbacks, too.
Take Fairweather Followers: If it is summer and an event cards is played, stand it. If it is winter and an event card is played, kneel it. Both would have to happen, so the First Player would choose the order. So you essentially give the First Player power over whether the character is standing or kneeling each time an event card is played. Hmm....
Or how about the Kings of Summer Agenda. If it is summer, draw an extra card. If it is winter, draw one less card. Both would apply, and cancel each other out.
Or what about Summer's Champion. "If it is Summer, Summer's Champion gains renown. If it is Winter, Summer's Champion gets -2 STR and cannot be declared as an attacker or defender." So if it is both seasons, I have a 2-STR, 2 icon character with Renown that cannot attack or defend....
So you see, it is intriguing, but in most cases, you don't get much out of it.
Winter Tax is about the only card that's worth using this with, and you'd have cards from 3 different Houses in the combo.
Xenu's Paradox said:
How do you figure?
Winter Tax
If it is Summer, attached card's owner needs 1 additional power to win the game.
If it is Winter, attached card's owner needs 1 less power to win the game.
Don't these just cancel each other out? No change in power needed to win the game?
Or did you mean Taxed Dry?
If it is Winter, attached card does not provide an income bonus.
If it is Summer, when you count income you may also count the income bonus on the attached card.
But that also, essentially, cancels itself out. You get to count the income bonus on the card, too, because it is Summer...but the income bonus is 0 because it is WInter.
~Winter Tax doesn't exist and Taxed Dry discards itself, so why bother? 
Rogue30 said:
ktom said:
I find it funny that income providing card does not provide an income bonus. It could be worded a little better 
Totally meant Taxed Dry.