Artefact summaries may contain spoilers
Scene summaries may contain spoilers
You see the workers from a window - they look fine. As you wait to see Sam's uncle, Van Ark, you overhear him talking with a scientist about the Crystal Palace Exhibition. The scientist begs Van Ark to let her help someone called Maxine, but is refused. Sam tells Van Ark he's heard rumours of missing workers, and is told to quash them.
You and Sam are shown to the excavation site, which is fume-free and not the main tunnel. Someone is hit by falling stones and you go to check if he's safe. You discover he is Phil, an undercover reporter. You cover for him when the overseer confronts him, then let him know you are looking for the missing workers too.
Phil shows you and Sam to the main tunnel. He tells Sam he knows Van Ark isn't his biological uncle, but worked with his parents before they died and then became his guardian. Phil has been told to pursue a story a story on a hypnotized workforce. The air begins to smell, so you all don breathing masks.
The smell in the tunnel is terrible. You find unresponsive workers beating pickaxes in unison to a horrible tune. Phil thinks they might be hypnotized by the music so you decide to find it and shut it off.
You find the music box playing the horrible tune and turn it off. The workers drop their pickaxes and advance on you. Their flesh is rotten. The overseer arrives and confronts you, but is bitten by a worker. She throws a wrench at the worker's head, but misses. You all run away down the tunnel.
You barricade yourselves behind a door, but the risen dead workers are pounding on it, shaking the supports. The overseer tries to convince you to cut off her bitten arm. She says the plague is in her blood, passed on through the bite. It overtakes her, and you flee.
There's a ladder up ahead. You realise that if you let the undead out, the plague will spread through London. The undead bring the tunnel down on themselves as you escape up the ladder to safety. You vow to find out more, and put a stop to it.