Still nothing. Wada knelt and stretched out her free hand to where the Irishman lay, his face flattened against the floor, his eyes gaping like those of a giant tuna on the slab at Tsukiji Fish Market. He had to have the key to the handcuffs somewhere about him, but, even lying down, she couldn’t reach beyond the left sleeve of his parka.

He didn’t seem to be breathing. It came to her then that he might be dead. She wasn’t certain. He might just be unconscious. And how long he’d remain unconscious she didn’t know. But while he was, they had to act.

‘Mr Caldwell!’

No response. He was hiding somewhere. He had to be. Perhaps he feared she was trying to lure him into a trap at the Irishman’s bidding.

‘I tripped him up and he has knocked himself out,’ she called. ‘We have to take this chance. But I am handcuffed to the basin. I cannot reach him. Or the gun. Please come. Now.’

At last, there was a sound, faint and ambiguous. But it was something. And soon it became a succession of sounds that were surely footsteps in the passage, drawing slowly closer.

‘Mr Caldwell?’

And then there he was, in the doorway, looking in at her and the Irishman. He was trembling. His breathing was fast but shallow.

She rattled the chain of the handcuffs. ‘You see?’

‘What … what happened?’ he asked in a voice hoarsened by stress.

‘I told you. Please search his pockets, Mr Caldwell. We need to find the key for these handcuffs.’

‘Is he dead?’

‘I think he may be.’

Caldwell moved cautiously into the room and stooped over the body on the floor. He pressed his fingers to the side of the Irishman’s neck. ‘I can’t feel a pulse,’ he said. ‘Hold on.’

There was a round metal-framed mirror hanging on the wall above the basin. He took it off its hook and, kneeling carefully clear of the pool of blood, held the glass close to the Irishman’s mouth and nose. Several slow moments passed. Then he glanced at the mirror and turned it round for Wada to see. The glass was clear. The Irishman wasn’t breathing.

‘It seems you’ve killed him, Miss Wada. What do you think we should do with him now?’

‘Just find the key.’

Caldwell nodded and began working his way through the Irishman’s pockets. He pulled out a passport and a wallet from one. Opening the passport, he grimaced, then laughed oddly.

‘What is wrong?’

‘His name. Ohara. That’s why they call him the Irishman. I suppose they think it’s funny.’

Wada wanted to ask who they were, but decided that could wait. ‘The key, Mr Caldwell.’