“This is the first time,” Tom said, “we actually know where we’re going.”

No one stopped us; we’d been seen enough around Whitehall the past few days that our faces were familiar. We watched carefully the whole time, but seeing nothing out of the ordinary, we moved on.

The arrow directed us outside, through the Stone Gallery, and suddenly we were in the Privy Garden. We skirted the garden itself, heading south until we reached the apple trees that lined the edge of the grass.

“Which tree should we look at?” Sally said.

The X had been marked over the third tree up, but there were more here than the map showed. “Let’s start at the third from the end, and go from there.”

“What are we looking for?” Tom said.

“I don’t know. Maybe an actual X?”

“The little arrow is aimed at the ground,” Sally noted.

“So let’s look there, too. Maybe what we’re trying to find is buried. Check to see if the earth has been disturbed.”

There wasn’t enough light to see in the orchard; we had to run back inside to get lanterns. Then we began to search. Sally checked the bark for marks. Tom and I inspected the soil around the trunks. He reached the fifth tree before he called to me. “Christopher.”

I went over. He knelt on the grass in front of a darker spot on the ground. The earth here had been turned over recently, then patted down.

Tom was already digging his fingers into the dirt. He rooted around for a moment, then stopped. “There’s something.…”

He pulled out a little object wrapped in cloth. He shook the soil off, then unfolded the wrapping. Metal glinted in the flame.

It was a key.

“What does it open?” Sally said.

“I’m guessing whatever we find at the end of the arrow,” I said. “Let’s go.”

CHAPTER 44

WE WENT FASTER THIS TIME. The arrow led us past Westminster Gate, over the tennis courts, then back into more apartments, until we reached the room where the arrow ended. It was beside the old tiltyard, where knights had jousted in the days of Elizabeth and Henry VIII.

On the map, this room was circled. It was one of three rooms listed with the number 33. The door was closed.

“What now?” Tom whispered.

He and Sally kept watch as I knocked at the door, softly. When no one answered, I tried the knob.

Locked.

I remembered what Lord Ashcombe had said. Nothing is locked in the palace.

Fingers trembling, I inserted the key we’d found buried by the tree in the Privy Garden. It turned smoothly.

Clack.

I stood there, hand on the knob, but I didn’t open it. “Just a second,” I said to the others.

“Where are you going?” Sally said.

I hurried back through the corridor, catching up to a pair of servants we’d passed along the way. “Excuse me?”

I showed them my map, keeping the message with the long arrow hidden. I pointed to the quarters marked 33. “Could you tell me whose rooms are these?”