Jack and Akiko joined Yori at the casement window. Under the silver sheen of the moon, the four plague doctors stood in a line, their black gowns flapping in the chill breeze like crows’ wings. Moonlight was reflected, ghostlike, in their glass eyes; their beaked masks appeared deathly white, terrifying to behold. Sir Henry’s guests were fleeing down the gravel paths, keeping as far away as possible from these harbingers of pestilence. But it was the very disorder of their flight that threw into sharp contrast the plague doctors’ unnatural stillness.

Akiko frowned. ‘They’re not moving …’

‘But why not?’ asked Yori, squinting to get a better look. ‘Do you think they’re waiting for everyone to leave before attacking us?’

Studying the layout of the ornamental garden below, Jack’s eyes widened in grim comprehension. ‘No!’ he gasped. ‘They’re not moving because they’re statues! The ninjas have covered them with their plague doctor clothes. It’s a trick!’

Suddenly a shadow appeared at the window, only a pair of eyes gleaming in the dark. A small diamond of glass was knocked from its lead frame and a blowpipe pushed through.

‘Watch out!’ cried Yori, throwing himself at Jack. They both fell to the floor as a poisoned dart shot out of the pipe. Missing Jack by a fraction, the dart embedded itself in the nearest post of Rose’s four-poster bed. Jess let out a startled cry and dived under the bed for cover.

Before the ninja could reload another dart, Akiko spun on her heel and back-kicked the casement window. Glass shattered and the frame flew open, sending the ninja plummeting earthwards. A second later, they heard a distant splash as the assassin fell into the moat. Akiko leant out of the broken lattice to see the dark figure swimming for the bank. ‘He’ll be back,’ she warned. ‘Have no doubt of that!’

‘Hey, what’s going on in there?’ shouted Sir Francis, his voice muffled by the door.

‘Nothing,’ Signor Horatio replied casually. ‘I’ve just dropped the water jug, that’s all.’

‘Thanks for saving me,’ said Jack, as Yori helped him to his feet.

Yori smiled. ‘It’s becoming something of a habit here in England!’

‘At least we have a way out now,’ said Akiko, inspecting the brickwork for possible handholds.

However, before she could climb out of the window, they heard Sir Edmund’s tremulous voice in the corridor. ‘Wh-wh-who goes there? Relight the lamps! Show yourself!’