Having explained his business to the captain and seen Douglas securely locked in a cabin, Tanner stood leaning on the rail of the upper deck, watching the pleasantly situated town slip slowly astern. He could see the Cathedral of Belem standing, damaged, just as it was left by the earthquake of 1755. Then out of the mouth of the river and past the picturesque pleasure resort of Mont Estoril, with, just beyond it, the sleepy, old-world village of Cascaes till, rolling easily in the Atlantic swell, they turned northwards. The Burlings Islands, which they passed later in the day, were the last land they saw until, on the third morning, they awoke to find themselves lying in the Mersey. By midday Tanner and his prisoner were in London. CHAPTER XIII. Blackmail? When Inspector Tanner reached his office in New Scotland Yard, he found an instruction from Chief Inspector Edgar, informing him that Mr James Daunt, of Lincoln’s Inn, had important evidence to give him relative to the Ponson case. Accordingly, after he had made a formal report on his Portuguese expedition, he called up Jimmy and arranged a meeting. A few hours later he was seated in the solicitor’s office, smoking one of the latter’s best cigars. ‘My Chief says you have something to tell me?’ he began, after mutual greetings. ‘Why yes,’ Jimmy replied. ‘Did your Chief tell you what it was?’ ‘Didn’t see him. He’s in Manchester.’ ‘I fancy you’ll be surprised. You recollect you told me you had suspected Cosgrove Ponson, but that he had established an alibi and so must be innocent?’ Tanner nodded as he drew at his cigar. ‘That’s right,’ he agreed. ‘You were satisfied the alibi was sound?’ ‘Absolutely.’ ‘It’s a fake,’ said Jimmy quietly. Tanner took his cigar out of his mouth and looked at the other. ‘Get along now, Mr Daunt,’ he answered. ‘You’re trying to pull my leg.’ ‘No. The thing’s a fake right enough. Cosgrove was at the boathouse that night.’ Tanner stared incredulously. ‘You seem in earnest,’ he said slowly. ‘But you’ve made a mistake. I went into it carefully. There’s no doubt it’s sound.’ ‘It’s _you_ that have made the mistake,’ Daunt answered pleasantly, and he went on to tell the Inspector what he and Lois had done, and all they had discovered. To say that Tanner was amazed and disappointed would be to understate the case. He was woefully chagrined. ‘God bless my soul!’ he cried, ‘but that sort of takes a chap down. Here was I looking down on you and that splendid girl as a pair of meddling nuisances, and I’m blowed if you haven’t had it over on me all the time.’ ‘Well,’ said Jimmy, ‘tit for tat.’ The Inspector eyed him almost aggressively. ‘And what now?’ he demanded. ‘Why this. I’ve told you what we did about Cosgrove. Now you tell me what took you to Portugal.’