Chapter IV: A Vital Enterprise

 is a Sunless Sea Story Event.

Story description
''The Chief Engineer emerged from underground with a motley assortment of other rats: he introduced them as weapons experts, strategists, and field commanders. "So you're going to help us beat the Cavies," he said, a hard edge to his voice. "But how exactly?"''

Trigger conditions
 is triggered when you do the I finished my exploration action in Chapter III: A Rat In The Making.