Have a conversation. Officially set by the Hollow Knight game, after it sits down in the Blue Lake, its special mission will be triggered. Quiruo will have a conversation with its Hollow Knight. After the conversation, you can go to the mission. "Hollow Knight" is a 2D action-adventure game developed by Team Cherry, a small team of only three people from Australia. It was released on the PC platform on February 25, 2017.