Ida's chest burned and her breathing came in ragged gasps. She was aware that her hair was now coming loose from its various pins and that her face must be glowing scarlet, but a fierce stubbornness kept her placing one foot after the other, chasing after Holmes. She was not going to let him take all the credit for locating Emily Hertford – he had even told Mr Hertford that he wasn't going to try, he had no right to do this…

Holmes stopped short suddenly, and she nearly cannoned into the back of him.

'Hey!' he shouted, 'hey!'

but not at her. He was summoning a nearby hansom cab with a wave and a shout. Ida looked round, panting, to see where Emily's cab had paused behind some other traffic a little further up the road. She hoped that the commotion caused by their running hadn't alerted its occupants to her and Holmes' chase.

Holmes was now climbing into his cab

'A guinea if you keep that cab in sight,' he instructed the driver, 'but not too close, mind…'

'Wait for me!' Ida managed to gasp out, stumbling towards the cab and clutching at the shaft which harnessed the horse.

'Miss Greene,' began Holmes,

'We haven't got time to argue,' pointed out Ida.

A brief second passed in a glaring contest, with Ida resolutely hanging onto the shaft, daring him to forcibly remove her. The driver observed the scene with an expression of bemused amusement. Eventually, Holmes leant forward. Ida tensed…

'May I, Miss Greene?' he asked with withering sarcasm, offering her his hand to help her on board.

…….

Seated inside the cab, Holmes was a study in taut deliberation, his gaze fixed on the street ahead and his cheeks sucked in slightly. He did not seem in the most talkative of moods, and Ida was still fairly out of breath, so she concentrated on trying to still her madly thumping pulse. After some minutes had passed in this way, the cab rattling its way along the street all the time, Holmes suddenly leant forward, elbows on his knees, saying

'How do you know Daniel Trelawney?'

Taken aback by the question, Ida opened and shut her mouth stupidly

'You don't know Daniel Trelawney,' Holmes answered his own question, in a matter of fact tone, and leant back once more.

Annoyed, Ida almost contradicted him just for the hell of it, but bit back her words. So. Daniel Trelawney. Was that the identity of Emily Hertford's male companion and - if what she had seen in the café was to be believed - fiancé?

She searched the street ahead for the cab they were following, and realised that she had neglected to memorise anything in particular about it, so had no idea which of the three she could see it might be. She hoped that Holmes and the cabbie had been a little more observant.

'They're turning into that street, guv, you want me to follow them?' asked the driver, and Ida saw that one of the hansom cabs had indeed just turned into a small residential side street.

'No,' said Holmes, slowly, 'no, this will be fine…'

'What?' exclaimed Ida, 'no, let's follow them!'

'That street is a cul de sac, and a narrow one at that,' Holmes explained, 'hardly the most discreet mode of entry to barge in behind in another hansom cab…'

He did not wait for Ida to reply, but instead turned his attention to the cab driver,

'A guinea, as promised.'

'Thanks!'

…….

In a matter of seconds they were poised by a pillar box near the entrance to the cul de sac, peering round the corner

'Don't stare so!' hissed Holmes, 'we can't both look in the same direction…'

Biting her tongue, Ida did as he said, and directed her gaze instead at the post box, reaching into her bag and pulling out her fake reference papers to keep up the charade.

'What's happening?' she murmured

'He's helping her out of the cab,'

Ida shifted restlessly.

'They're going into one of the houses.'

'Remember which one!' blurted out Ida,

'I can assure you, Miss Greene,' said Holmes, wearily, 'that I will be able to recall which one.'

He turned away from the scene

'Can I look now?' she whispered

'If you must,' said Holmes, 'but there's nothing to see.'

Ida looked into the quiet street of terraced houses, then turned back to Holmes questioningly. She was surprised to see his shoulders bowed in what almost seemed a gesture of defeat.

'Mr Holmes…' she began, uncertain what exactly to say,

He pinned her with his eyes once more and the words dried in her mouth

'I think we need to have a little talk, Miss Greene,' he said