So I'm trying to find a trilogy of books I read when I was a teen.
It started on a cruise ship, the protagonist is this kid, on vacation with his parents I believe (or just dad?) and he meets this girl, all dressed in white during the trip. She doesn't talk or acknowledge him and the dad's girl says that she is autistic.
Fast forward, the ship gets stuck in ice, I guess? And they have to go to this Antarctic Lab. Boy notices that the spiders all crawl outside of the lab and freeze outside as if they are running away from something in the lab.
I remember at some point that the author describes a spider as big as a Yorkshire Terrier, that really stuck to me. I also remember this being about Nyarlathotep and him being represented as a huge sea monster underneath the ship and wanting to wreck the world.
Also the girl wasn't autistic at all and it was just stuck inside her mind, controlled by the dreams of this old god.
I read this in 2008, I'm pretty sure as I was going to get into my 12th Grade. The covers were all with an octopus grabbing some sort of object (a diamond?), the first cover was in blue, I'm 100% sure. I've also read these books in Portuguese but I cannot remember the publisher company.