Logan McRae. Stuart MacBride

warbled away in questionable three-part harmony, a pink-faced Shona hauled in a breath and blew out the candles on her cake. Everyone cheered. Then a handful of them produced party poppers and set them off, draping her with streamers.

      Bevan smiled at them all. ‘All right, all right. You can have a lot of fun without being stupid.’

      Speaking of which …

      Logan sidled over to Tufty and Karl – both of whom were wearing their party hats at very rakish angles – while Shona cut the cake.

      ‘Have you pair managed to find anything?’

      A pout from Tufty. ‘Karl won’t let me have any more Red Bulls.’

      Karl bared his teeth in a big broad smile. ‘I have to say, Logan, your young friend here is quite the kid who whizzes, oh my, yes.’ He gave Tufty a wee playful punch on the shoulder. ‘But I’m afraid we’ve hit an impasse. Brave Sir Tufty’s algorithmic methodology is inspired, but without more computing power, it’s like trying to push a ten-tonne blancmange uphill wearing nothing but flip-flops and an amusing hat.’ He raised his to the height of its elastic, then let go so it pinged back down again.

      ‘Cake?’ Superintendent Bevan appeared, bearing three paper plates with slabs of yellowy sponge on them. She handed one to Karl. ‘Here we go.’

      ‘Ooh, my! Is this the sainted cake of lemon drizzle I see before me?’ He helped himself to a mouthful, chewing with his eyes closed. ‘Divine!’

      She gave one to Logan and the other to Tufty. ‘Birthday lunch at one o’clock. Logan’s brought enough sausages to feed a battalion.’

      Karl slapped him on the back. ‘Good man.’

      Bevan wandered off to distribute more slices and Tufty filled his gob, getting crumbs all down himself, mumbling through his mouthful. ‘If we had access to a bunch of high-powered servers we might be able to do something about it.’

      ‘But, alas, we are deficient in that kind of kit. So I’m afraid we’re done.’

      Ah well, it’d been worth a try.

      Logan took a bite of cake – sharp and sweet and bursting with lemon. ‘So if I could find you someone with a bunch of dirty big computers, you’d be able to track down whoever sent that first tweet?’

      A shrug from Karl. ‘Possibly.’

      A cakey grin from Tufty. ‘Definitely!’

      ‘Well,’ another shrug, ‘we’d stand a much better chance, anyway.’

      Logan polished off the last of his cake. ‘Then I know just the person.’

      Tufty cracked a yawn that made his head look like an open pedal bin, then shuddered and burped in the passenger seat of Logan’s Audi. Smacking his lips as he settled back again. Another yawn.

      Logan took one hand off the steering wheel to give Rip Van Tufty a thump on the arm. ‘If you start snoring and farting, I’m throwing you out of the car.’

      Aberdeen slid past the Audi’s windows, the traffic thickening along the bypass like clumps of fat in a swollen artery.

      Another yawn from the passenger seat. ‘Tufty needs caffeine.’

      ‘Well, what did you expect, staying up on a school night? You knew you had work today.’

      ‘But I was beavering for the greater good!’

      ‘Lucky Rennie covered for you, otherwise you’d be up for a spanking, you silly wee—’ Logan’s phone vibrated in his pocket, then the car’s hands-free system got hold of the call, flashing ‘SUPT. BEVAN’ on the central display and blasting his generic ringtone out of the speakers. On, and on, and on, and on.

      Tufty reached for the display. ‘Aren’t you going to—’

      Logan slapped his hand away. ‘No.’

      ‘Oh.’ He pulled on a sappy look. ‘She does make a lovely lemony drizzle cake, though.’

      Traffic was backed up around the next exit, giving everyone plenty of time to stare down into other people’s gardens. Logan changed lanes, bypassing the bypass’s vehicular clot.

      Tufty puffed out his cheeks. ‘Saaa-aaarge? You know there’s all this controversy surrounding—’

      ‘If this is about loop quantum gravity again, I swear to God I’m going to pull this car over and stuff you in the boot.’

      ‘Ooh, I do like a bit of loop quantum gravity, but no, it’s like, you know all this stuff going on with Alt-Nats hating Unionists? Well, this guy on the BBC website was blatant racism, yeah? But the English aren’t a different race, are they?’

      ‘I should’ve taken Karl with me. At least he’s fractionally less annoying.’

      ‘No, but listen,’ Tufty turned in his seat, bleary little eyes all shiny and dark, ‘you can’t tell someone’s English by looking at them, can you? And what does being English even mean? Rennie says Berwick-upon-Tweed used to be part of Scotland, right? So if you were born there on the twenty-third of August 1482 you were Scottish, but if you were born on the twenty-fourth you were English, but you’d still be the same person, wouldn’t you?’

      Logan groaned. ‘I’ve changed my mind: go to sleep. I don’t care if there’s snoring and—’

      His phone burrrrrrred again, but this time it was ‘IDIOT RENNIE’ that appeared on the dashboard display as ‘If I Only Had a Brain’ from The Wizard of Oz burst out of the speakers. Well, tough: he wasn’t getting answered either.

      ‘So it can’t be racist to hate the English, it’s nothing more than good old-fashioned Scottish bigotry. Like when Rangers and Celtic supporters hate each other, because one lot don’t like the other lot’s flavour of Christianity.’

      The tune faded away into nothing. Either Rennie had hung up, or it’d gone through to voicemail. ‘Tufty, am I not having a bad enough day as it is?’

      ‘I was supposed to be born in Glasgow, but my mum and dad didn’t want me growing up with all that, so they moved up to Banff instead and raised us secular, because—’

      ‘Please shut up, before I kill you.’

      ‘No, but you see—’

      It was Tufty’s phone’s turn, warbling out something cheery in a brass-band kind of way. ‘Hey, hold on.’ He dug it out and took the call. ‘Hello? … Ooh, Sergeant Rennie, cool. I was telling the Sarge what you told me about Berwick-upon-Tweed and how it— Ah … No. Yes … Sorry.’

      Logan raised an eyebrow. ‘Wish I knew how to get you to shut up that quickly.’

      ‘Yes, he’s here … OK … OK, I’ll ask him.’ Tufty put his hand over the phone. ‘It’s Sergeant Rennie. He says Superintendent Bevan wants to know why you’re not at DHQ helping DI King. Apparently, she’s not angry, just disappointed.’

      Of course she was. Once a schoolteacher, always a schoolteacher.

      ‘Tell him to tell her we’re on our way now.’

      A puzzled look stumbled across Tufty’s face. ‘But we’re not, we’re—’

      ‘Well Rennie doesn’t need to know that, does he? And if we get access to a load of high-end computers it is helping King out, isn’t it?’

      His eyes widened. ‘Oh yeah …’ Back to the phone. ‘Hi, uh-huh, we’re on our way there now, so tell her not to worry … No, there wasn’t anything suspicious about the length of that pause … Nope … OK, bye.’ Tufty hung up. Grinned. ‘Didn’t suspect a thing.’

      If that was true, there was no hope for Police Scotland.