Complex sentence: Yennefer finds Geralt and Vesemir after an incident in the tavern and tells Geralt that Emhyr var Emeris, the Emperor of Nilfgaard, has summoned him to Vizima, the capital of Temeria occupied by Nilfgaard.
Split into simpler sentences: Yennefer finds Geralt and Vesemir after an incident in the tavern. Yennefer tells Geralt that Emhyr var Emeris, the Emperor of Nilfgaard, has summoned him to Vizima, the capital of Temeria occupied by Nilfgaard.