The Witcher 4's cinematic reveal trailer was an indulgent six-minute-long saga in which Ciri, the new protagonist of the series, went on a sidequest. The whole thing had the vibe of the Killing Monsters trailer for The Witcher 3, or that one quest where the villagers have been offering sacrifices to leshen.
It begins with someone getting into a bath, only this time it's not Tub Geralt. It's a young woman being prepared for a ritual while her father narrates about how he watched her grow up. That's intercut with footage of Ciri, a character we watched grow up, though we don't see her face. She's using the igni sign to light a fire—possibly burning some herbs to prepare a potion with. Ciri continues to prepare by sharpening a sword, one that looks like the silver version of Zireael seen in the ending of The Witcher 3 where Ciri follows in Geralt's footsteps.
As the young woman walks out into a crowd of her fellow villagers, one of them spots the distinctive paired swords of a witcher among them. He lays a hand on the witcher's shoulder, and as she turns we see Ciri's face for the first time. She's older than she was in The Witcher 3 (and doesn't sound like she's being voiced by Jo Wyatt any more), and has the pupils of a witcher. That means she's undergone the Trial of the Grasses, or at least a version of them, which previously only young boys were able to survive. Perhaps Ciri made it through them thanks to her Elder Blood?
Or maybe the School of the Lynx has their own formula, cooked up in the years between games. When Ciri arrives at the cave where our young lady's gone to be sacrificed, her witcher medallion vibrates, and it's a distinctive lynx like the one we saw in an early tease for The Witcher 4.
During the fight that follows, Ciri downs a Cat potion to be able to see in the dark (and to boost her crit chance by 5%, assuming she downloaded the 4.0 patch). Given that the poisonous potion doesn't kill her, that's more evidence she's undergone the Trial of Grasses and become a full witcher. In the fight that follows she relies on swordplay and signs rather than her ability to teleport, perhaps because those abilities were reduced in strength after defeating the White Frost.
Ciri does draw on some water running down the cave wall to empower a chain around her fist, which then electrocutes the monster she's fighting. It's a cute callback to the way Geralt used a chain against the striga in the first game's opening cinematic, but Ciri's clearly capable of more magic than Geralt was. Perhaps she'll regain her abilities over the course of the story, like Batman learning his skills again in each Arkham game?
The trailer ends with Ciri defeating the monster, only to discover the villagers have done its work and killed the sacrifice anyway in the name of the gods. It's a typically downbeat Witcher ending. "There are no gods here," Ciri says. "Only monsters."
And then, though only in the version of the trailer shown at The Game Awards, we get to hear Geralt. "Time for a new saga," he says. "See you on the path." Given the back-and-forth about whether Doug Cockle's Geralt will be returning in The Witcher 4, this seems like a last-minute addition to make sure we know that Geralt hasn't been completely cast aside. Maybe he'll play a mentor role, like Vesemir did in The Witcher 3. Or maybe he'll just be chilling in his vineyard, playing Gwent.
We'll have to wait a while to find out, given that The Witcher 4 only just went into full production.