He's running out of options and allies.

It does appear that he is running out of options. He is always scheming so he is of course up to something. I imagine it is to cause disruption among the Starks, create chaos, and climb his ladder to a better position. I don't see it working though. He loves Sansa (or is at least infatuated) so I'm sure we will see just how far that love goes. Will he be able to sacrifice himself or his ambitions for her sake? I don't think we've ever seen him do that for anyone.

It looks like his idea was to create a rift between Sansa and Jon and present himself as her protector. But having Bran and Arya both pop up is going to complicate that.

Related question -- why was Arya giving him that look of hatred? She doesn't know that he betrayed Ned. The last time she saw Littlefinger was when he spotted her in disguise at Tywin's and didn't blow her cover; that would be a positive impression.

Interesting question -- does Littlefinger have any links with the Faceless men, and did Arya hear something there about him?

@CharlesTheBold said:

Related question -- why was Arya giving him that look of hatred? She doesn't know that he betrayed Ned. The last time she saw Littlefinger was when he spotted her in disguise at Tywin's and didn't blow her cover; that would be a positive impression.

Interesting question -- does Littlefinger have any links with the Faceless men, and did Arya hear something there about him?

Yes, good points here....And I think you helped me figure what I think....she knows the Lannisters orchestrated the wedding attack with Walden, pretty sure.....She knows the Lannisters killed Ned....So then she saw Littlefinger at Tywin's so she considers him in with the Lannisters maybe in general?...Just maybe someone not to be trusted due to him being close to Tywin and other Lannisters?

I got the impression she knew who he was and knew he was bad in her mind...

Concerning Littlefinger's nickname:

I read somewhere that back in Shakespeare's time, "little finger" was a euphemism for a certain masculine organ. The term even got into the Bible when King Rehoboam boasts about the size of his "little finger" in the Book of Kings.

Did Martin know that, and did he give the nickname to Baelish for that reason?

I think Little FInger's game is to somehow wind up owning the person sitting in the iron throne. From what I am seeing - he started this whole show in motion by getting Jon Arryn (sp?) poisoned by his wife. That brought The King to Winterfell and the Starks followed them back to Kings Landing. So, he has been the puppet master this whole time.