Grand investigations

Investigations are the main story mode quests.

The following investigations are available:
 * The Martyr
 * Chapter 1
 * The Abandoned Colossus
 * The Cage
 * The Expedition
 * Chapter 2
 * Saving Caius Thorn
 * Hunt for the Martyr
 * Chapter 3
 * Klosterheim
 * Revelations
 * Machine Spirit
 * The Secret Weapon
 * Rebellion
 * Chapter 4
 * Van Wynter Legacy
 * Through Fire and Flames
 * Uther's Tomb
 * Chapter 5
 * The Alpha Pariah
 * The Thing in the Walls
 * Choas Undivided
 * The Enemy Below
 * Viper's Nest
 * Harbingers of Hate
 * Drukhari Menace
 * Terra Incognita
 * Grim Harvest
 * Shadow of Commorragh