Chapter 4 followed on from the video at the end of Chapter 3:The Lower City ; Kain had found Sanctuary hidden under Blue Lady Curios, but had also discovered that Umah's mission to The Industrial Quarter had been compromised and she had been captured by the Sarafan and taken to the Sarafan Keep. In order to find the secret entrance to the Sarafan Keep, Vorador sent Kain to the Upper City to find the Bishop of Meridian, who knew it's location.
Shortly into the level, Kain met traitor Vampire, Marcus, who tried to subjugate Kain's mind using his Dark GiftCharm. Marcus failed to control Kain, but was able to read his mind, learning that the Bishop had important information for Kain. Marcus immedietly set off to reach and Kill the Bishop before Kain could get his information. Kain spent the majority of the rest of the level in pursuit of Marcus (using rooftops and sewers to avoid the Sarafan and Ward Gates on the main road).
Kain arrived at the Bishop's Manor shortly behind Marcus and found from Cabal Contact butler, that the Bishop had already fled via a secret passage to Meridian Cathedral. Arriving at the Cathedral, Kain found the Bishop, apparently in a catatonic state. Rather than follow Marcus' instructions to spare the Bishop's life, Kain instead charged Marcus, aiming to kill him first. Kain pursued Marcus around the Upper City and back to the Cathedral roof, where both Vampires fell through a stained glass ceiling, ending up battling in the Cathedral again. Kain was able to use the Cathedral Bells to deafen Marcus and defeat him (see Marcus (boss)), absorbing his veins and gaining the Dark GiftCharm and allowing him to talk to the Bishop, who was able to direct Kain to the secret entrance to the Sarafan Keep and Chapter 5[Blood Omen 2].
Despite this level being subtitled "the Upper City ", it does not entirely take place within the confines of the Upper City, shortly after he rings the bells to make the workers open the gates, Kain appears to briefly cross into the Industrial Quarter[1][2] before using a lift there to get to a higher vantage point and Jumping back[Blood Omen 2]. At One point during the chase with Marcus, the camera can be moved to showthe Device in the background (with a prominent green glowing symbol)[Blood Omen 2].
↑Vorador: (Whispering)"Kain, the Bishop’s manor is near. However, the Seraphan patrols have locked down all the streets. You may be able to trick them into opening the gates. Find the clock tower, and ring its bell. The workers will think it time for their shift to change, and will open the gates." Crystal Dynamics. Blood Omen 2. (Eidos Interactive). PlayStation 2. (March 19, 2002) Transcript.