Here’s the relevant piece of the exchange, after Littlefinger offers to attack Winterfell with the Knights of the Vale:“And if you succeed?” Cersei says“Name me Warden of the North,” Littlefinger says.“I’ll speak to the king this evening, have him issue a royal decree.”“I will not rest until the Lion flies over Winterfell,” Littlefinger says, in reference to the Lannisters’ house sigil.“I’ll know you’re a man of your word when I see Sansa Stark’s head on a spike.”So that’s not a super good sign for Sansa. Littlefinger won’t even have to attack Winterfell, since his knights are already the occupying force. Not only that, but the Stark’s trump card, Wun Wun the giant, is dead. Maybe they're not as unstoppable as we thought There are a few ways this could go. First, Littlefinger could keep his word to the Lannisters. Though Cersei is no longer in control of the king, presumably the royal decree still stands. Second, Littlefinger could decide he loves Sansa more than he wants power . That seems unlikely given that he's kind of all about power. Third, he could lead his own force south and fight against the increasingly disorganized and dispirited Tyrell and Lannister armies while they’re fighting the Faith Militant in King’s Landing.Whatever happens, Sansa is in a lot worse trouble than she realises.