
This is what caused the Necromorph outbreak and the widespread insanity among the crew. As discovered at the end of the first game, an object called the Marker was discovered on Aegis Vii and brought on board the Ishimura.

Isaac must fight his way across the Sprawl, fighting new types of necromorphs and struggling with dementia and vivid hallucinations throughout. A necromorph outbreak is taking place and the entire city is being overrun and reanimated.

The Sprawl is hundreds of times larger than the USG Ishimura, which is where almost all of the first game took place. You play as Isaac Clarke, who has woken up in a mental institution on the Sprawl, a gigantic city surrounding a shard of Saturn's moon, Titan. Dead Space 2 takes place place 3 years after the events of the first game.
