Chapter 543, "The Tree Father's plan", is the clearest early answer because it turns Robin Burton's situation into a concrete plot event.

Chapter 238, "A quick plan", is the clearest early answer because it turns Robin's situation into a concrete plot event.
Chapter 978, "Crazy plan", is the clearest early answer because it turns Robin's situation into a concrete plot event.
Chapter 451, "Acceptance", is the clearest early answer because it turns Tree Father's situation into a concrete plot event.
Chapter 553, "Greed", is the clearest early answer because it turns Tree Father's situation into a concrete plot event.
Chapter 979, "Back-up plan", is the clearest early answer because it turns Robin's situation into a concrete plot event.
Chapter 540, "Provoking a tree father", is the clearest early answer because it turns Jabba's situation into a concrete plot event.
Chapter 595, "Stupid monsters", is the clearest early answer because it turns Tree Father's situation into a concrete plot event.
Chapter 734, "Tavina", is the clearest early answer because it turns Father Tree Tavina's situation into a concrete plot event.
Chapter 492, "Pride", is the clearest early answer because it turns Tree Father Hoffenheim's situation into a concrete plot event. The setup is Who exactly are you and what are you doing in our world?, but the pressure keeps building through Why are you attacking my domination circle?.
Chapter 559, "conversation with a tree father -3", is the clearest early answer because it turns Descartes's situation into a concrete plot event.