I am just curious about the timing of this card. I flip betrayal my opponent flips valar morghulis I'm first player and choose outwit as my new plot can I kneel my learned character to cancel valar or does valar resolve first before outwit?

1st player chooses the order of all plots revealed. So if you are FP, you can choose Betrayal, flip outwit, then choose Valar, then respond to cancel it.