Possible Clues:

• *Grayish time at dusk or dawn
• Dawn perhaps steps on Henry
• See most of manor with stairs in semi-darkness
• Prince running away in the gloaming
• Escape with prince in semi-darkness
• No time to stop before journey, a sign it's getting late
• Henry takes steps in partial darkness
• Almost completely stop air travel for dusk
• State of limited visibility almost put a stop to escape
• Henry taking steps in the gloaming