The primary focus for this season has been a mystery surrounding monoliths, huge chunks of black stone which stud the land, and which Ciri seems to have a unique ability to crack/damage by screaming. They seem to be bringing new monsters to the Continent from the other spheres of reality. The other main plotline has been a demonic creature called Voleth Meir, the "deathless mother": the first witchers were apparently created to combat her, and she has been trapped since then underground, until now. She attempts to cut demonic deals with Fringilla Vigo, Francesca Findabair, and Yennefer, offering them their desires... but she demands Yennefer deliver Ciri to her, and eventually possesses her.
These two plot strands are easily the most prominent in S2 of the Witcher, driving most episodes and serving as the climax of the season. Neither monoliths nor Voleth Meir are a thing in the books.
A secondary plotline surrounds the elves gathering as refugees at Cintra, where Fringilla has negotiated an uneasy truce between Nilfgaard and the elven leaders Francesca and Filavandrel. Francesca eventually falls pregnant and gives birth, but the child is assassinated, and the elves blame Redania. They travel north to exact vengeance, and Francesca goes full King Herod, slaughtering Redanian children. It then turns out Nilfgaardian emperor Emhyr ordered the assassination, in order to manipulate the elves into going to war with the Northern Kingdoms.
In the books, there is an agreement between Francesca and the Nilfgaardians, though it only comes up later, following the conclave of the mages on Thanedd. The elves head for Dol Blathanna, not Cintra, to form their own kingdom. Meanwhile, elven commandos do indeed fight against the Northern Kingdoms and assist Nilfgaard. She has made a grand-scale stategic and moral gambit; there is no child assassination plot manipulating her into doing so.
This TV plotline has really pissed me off, personally, because Francesca Findabair was one of my favourite characters in the book series: genuinely morally grey, doing what she believes is best for her people, and successfully creating a mostly-independent country (which they direly needed), but compromising her principles to do so, and assisting an aggressive empire in return for their support. She makes these decisions not lightly, but freely. The show has destroyed her characterisation. She is tricked into war, and resorts to slaughtering children as her first move-- pointless cruelty above strategy. There is no measured thought or big-picture compromised thinking here. She has been reduced immeasurably, and the Francesca of the books would simply never act like this.
Yennefer also acts dramatically out-of-character, nicking Ciri and attempting to trade her to Voleth Meir in return for getting her powers back, then having a last-minute change of heart (conveniently when Geralt turns up). She's also been reduced, to a flighty and easily-changeable individual who takes decisions lightly, endangers her allies for no justifiable reason, and then needs to be shoved aside and set straight before finally changing her mind and deciding not to sacrifice her friends after all.
Other characters who act in ways they never would include (but are not limited to) Cahir, Vesemir, Eskel, Istredd, Tissaia.
Personalities for characters have been almost entirely replaced, to the point where they scarcely represent the characters they are supposed to inhabit. Half of the plotlines are not only show-only, but are at total odds or fully contradict the books (the monolith plotline being the most egregious).
On the plus side, some of the performances are pretty solid, including Dijkstra and Yarpen Zigrin.
Blech. Don't think I'll be keeping up with it.
