In chapter 2 of The Lion, the Witch and the Wardrobe, when Lucy first enters Narnia, she meets Mr. Tumnus, a faun who invites her back to his cave for tea. In chapter 6, all four children enter Narnia together, and Lucy decides to take the others to visit Mr. Tumnus. When they arrive at the cave, however, they find it in disarray. The door has been wrenched off its hinges and smashed to pieces, the crockery has been broken, and snow is drifting into the cave. The children then find a piece of paper, on which they read the following message:

The former occupant of these premises, the Faun Tumnus, is under arrest and awaiting his trial on a charge of High Treason against her Imperial Majesty Jadis, Queen of Narnia, Chatelaine of Cair Paravel, Empress of the Lone Islands, etc., also of comforting her said Majesty's enemies, harbouring spies and fraternising with Humans.

The paper is signed by the Captain of the Queen's secret police. When Lucy first met Mr. Tumnus, he confessed to her that he had originally planned to hand her over to the Queen, who was anxious to capture any humans who came to Narnia. However, having met Lucy, he found he was unable to do this and showed her the way back home. When the children discover that Tumnus has been imprisoned for helping Lucy, they decide that they must rescue him, a decision which gives purpose to what, before this point, was an aimless exploration of the new country.