If u are using this agenda is their any real counter to this? i mean you could valar but with no claim seems very unlikly be able to comeback just with that plot being pretty common seems a big hurt to that agenda…

What do you mean by "any kind of counter"? Are you asking if there is any way not to get screwed by the fact that you'll have no more than 1 card in play until round 2. Probably not. There is no way to "shut off" the "no setup cards" requirement on the agenda.

Your best bet, really, is the plot "Forgotten Plans."

Although I'm not sure how common Fear of Winter is since it's on the restricted list.

First snow of winter is a solid cap because with their limited gold, they will likely only be able to have 1 character that is >3 cost. Forgotten plans is the best counter to it, but if they dont play it the plot is not the best. Loyalty money can buy or at the gates can both be solid first plots against it with a non KoHH deck, but with KOHH you need to go first snow of winter or forgotten plans.

First snow of winter is good when they have aggressively setuped their characters, they are probably also able to play a 3-4 cost character on the board. It can either slow them down or if they have board full of weenies then you could actually stall the entire first turn (if they make no challenges then nothing will bounce back as most likely you didnt use your 1 card for a character.
Forgotten plans is your best bet, no matter what they setuped and played you have foiled their Fear of Winter. Might not be as effective, but it is reliable.

I don't think it's too dangerous for the KotHH to face FoW first turn, you wont get no one killed (don't play a char), you won't have no power removed, as you have 0 at the beginning, and you might lose 2 cards from hand, depending on the rival setup and your counters (Flame Kissed for Targ, Red Vengeance, Cyvasse, etc for Martell), so the rival is aiming at 3 unnopossed and little more.

The worst part is you might have lost a good plot, and depending on more factors, you might be facing a T2 Rule By Decree, now that hurts . On the plus side, you might have less cards in hand and Rule (if you play it) might benefit you.

On the other side, as KotHH usually wants to play lots of card in a single turn (events, ambush chars, martell draw after play chars, etc) FoW does a huge damage in any other round but the first.