‘In a nutshell.’ The Doctor nodded. ‘Well, not literally a nutshell, that’d be far too small.’

  ‘How do you plan to lure them?’ Mileva asked, puzzled.

  ‘Bait.’ The Doctor looked at Einstein.

  Yaz’s jaw dropped. ‘You’re joking. You know what happens when he gets near those creatures!’

  The Doctor nodded. ‘Trouble is, they’re drawn to him, aren’t they? Way more than to any of the rest of us. His brain’s unique, processing sensory information faster than anyone else’s.’

  Yaz raised an eyebrow. ‘Faster than yours?’

  ‘The starfish have developed a taste for human thought,’ said the Doctor. ‘Anyway we can’t risk leaving him somewhere else. We need to make sure we get every last one of these brain-suckers, so we can take them somewhere safe.’

  ‘Where would be safe?’ asked Yaz.

  ‘I’ll find somewhere,’ said the Doctor. ‘It’s a big universe.’

  ‘No,’ said Mileva. She was shaking her head mutinously. ‘I can’t allow you to use him like that. It could make his mind collapse completely.’ She clutched the unconscious Albert to her breast. ‘What would I do without him?’

  The Doctor looked at her kindly. ‘You said you’d be willing to risk everything.’

  ‘Not him! I can bring the starfish – use me!’ Mileva insisted. ‘My brain is as good as his, sometimes better. We have worked together for years. Many of his research papers he worked on with me.’

  ‘He did?’ Yaz stared. ‘Then why isn’t your name on them?’

  ‘Because I am a woman,’ said Mileva, as though it were obvious. ‘You think they would allow a female mathematician to publish a scientific theory? You are living in a different world.’

  ‘You don’t know how true that is,’ said Yaz.

  ‘I can’t use you,’ the Doctor explained. ‘Look how drained you were after only a few minutes. You’d lose consciousness. Albert is the only one who can produce the amount of energy we need.’

  Albert began to stir.

  ‘He’s waking up,’ said the Doctor. ‘We haven’t got much time. Mileva, you said you knew of somewhere we could go? We need somewhere spacious. Indoor, preferably, with windows. Big empty room.’

  ‘The Rathaus,’ said Mileva. ‘It’s not far from our apartment.’

  ‘Town hall!’ exclaimed the Doctor. ‘Perfect! You get Albert there, Mileva and wait for us outside. Yaz and I will pick up some bits and pieces from the flat and join you as soon as we can. By the way, have you got a gramophone with one of those big trumpet thingies on top?’

  ‘Yes, why?’

  ‘I’ll need it for the amplifier.’

  Albert’s eyes opened. ‘Where am I?’

  ‘You’re with me, darling,’ Mileva assured him. ‘I’ll look after you. Can you stand?’ She helped him to his feet, and they staggered away.

  ‘Doctor,’ said Yaz in a low voice, ‘if Albert is awake and we bring all those starfish in – thousands of them – then …’

  The Doctor nodded. ‘Yep. The ghosts will come too. Lots and lots of them. They’ll flood the city. People will be in danger. That’s why we have to work really fast, Yaz. Else there might not be a city to save.’

  Yaz was thankful that the race to the Einsteins’ apartment was without incident. The Doctor was like a whirlwind, picking up all sorts of bits and pieces from the various rooms and thrusting them into Yaz’s arms. ‘Copper wire, pliers, ooh, hammer and nails, you never know, hold that, Yaz – kitchen, kitchen … forks! Yes – and a big metal saucepan. Does this fit on your head, Yaz? No, not quite. Never mind, found a bigger one, hold this – oh, you can’t – well, put some of the other things inside it …’

  Yaz followed, trying not to drop anything. The Doctor wrenched the horn from the top of the gramophone with a grimace. ‘Got everything?’

  ‘Er …’

  ‘Good! Let’s go.’

  They dashed back down the stairs, narrowly missing an elderly woman coming out of the flat below. ‘Hey, watch out!’

  ‘Sorry!’ the Doctor said breathlessly. ‘Got to save Einstein!’

  ‘Tell him he’s behind on his rent!’ the woman shouted back.

  They ran down the street, taking a left at the end. ‘I remember the Rathaus,’ the Doctor puffed. ‘Smart building, got a double staircase outside, like a big triangle. You can run up one side and down the other, brilliant!’

  Yaz glanced behind and gulped. ‘Doctor, what’s that?’

  The moon overhead was casting shadows into the street. Some of the shadows seemed to be growing …

  ‘Better speed up,’ said the Doctor.

  They found Mileva helping Albert up one of the stone staircases of the imposing Rathaus. ‘Come on,’ she was saying. ‘It’s only a little graze. You’ll be fine.’

  ‘What happened?’ Yaz stopped as the Doctor ran ahead to open the enormous wooden doors with the sonic.

  Albert turned burning eyes on Yaz. ‘I fell,’ he said, his voice taking on an added timbre of fear. ‘Look.’ He held out his arm, sleeve rolled back. From elbow to wrist there was a superficial graze.

  ‘He tripped and scraped it on a wall,’ Mileva explained.

  ‘Looks sore,’ said Yaz sympathetically.

  ‘It is deep,’ said Albert. ‘Deeper than it looks. You can see the blood springing to the surface, there!’

  Alarmed, Yaz looked at Mileva, who nodded. Again, Albert was seeing things that weren’t there. ‘Blood,’ murmured Yaz, glancing at the street, where the shadows were stretching across the cobbles. Perhaps they weren’t shadows after all …

  ‘Get inside, quick,’ Yaz said, her arms aching from the weight of all the items she was carrying. The three of them made their way through the arched doorway into a gloomy hall and from there into a large vaulted room.

  The Doctor, standing in the middle of the room, gave a sharp nod. ‘Right, no time to lose. Yaz, bring all that stuff over here. Mileva, find a chair and put it in the middle of the room. Albert, sit on it and don’t move.’

  ‘The blood,’ Albert muttered, examining his arm obsessively.

  ‘Yaz, jam these forks into the gaps between the floorboards just here, with the prongs sticking up.’ The Doctor pulled out the sonic and started untangling the copper wire.

  Yaz knew by now not to ask questions when the Doctor was firing on all cylinders.

  ‘Now open that big window as far as it’ll go. And find me a big box.’ Sparks flew from the sonic as the Doctor pointed it at the saucepan.

  Mileva had dragged two chairs into the middle of the room, and was sitting firmly next to Albert, her hand possessively on his knee while he peered nervously at the graze on his arm. ‘It’s getting worse,’ he said, his voice trembling. ‘See the beads of blood forming? And this drip, down to my hand now?’

  ‘My darling,’ Mileva said. ‘There are no beads, there is no drip. Look at me.’ But Albert didn’t hear her.

  The Doctor had a look at her own handiwork. ‘It’s not perfect, but it’ll do.’ The large saucepan now had several copper wires fused to the outside, long coils of them trailing down to the floor. Positioned by the window was the horn from the gramophone. ‘Here’s a lovely hat for you, Albert.’ She fitted the saucepan onto his head.

  He reached up for it. ‘What is this?’

  ‘It’s – an advanced machine for healing,’ the Doctor improvised. ‘It’ll slow down that bleeding you’re worried about.’

  ‘Oh.’ Albert subsided.

  Yaz staggered back into the room, carrying a large empty tea chest. ‘Is this big enough? Found it downstairs.’

  ‘It’ll have to do.’ The Doctor examined it. ‘Let’s hope the starfish don’t mind a game of Sardines. Now, all we have to do is wind these wires around the forks, and attach the ends to the trumpet thing.’

  ‘We’re amplifying Albert’s brainwaves?’ asked Yaz, winding wire around a fork.

  ‘S’right. Need to make sure we can broadcast him right across the city. And the forks are to secure the wires so any pesky apparitions don’t pull ’em out straight away.’ She changed the settings on the sonic and plugged it into her handmade machine, so that the ultraviolet beam shone on the open window. ‘Look at this!’ The window frame was already covered in starfish, and more and more were floating in. ‘Grab as many as you can and put them into the box. Mileva, you too. The aim of the game is to be the one who collects the most starfish and jams them into the box.’

  ‘And to be alive at the end of it,’ Yaz muttered.

  The bishop had finished his service and begun another. More and more parents were glancing anxiously at their children, as the quiet regular breathing turned to tiny gasps. Instinctively, they moved forward, nearer the altar, craning to hear words of hope and comfort, even as many of them were losing hope themselves. Friedrich and Marthe were bent over Johanna, whispering prayer after prayer, telling her how much she was wanted and loved.

  Graham was whispering his own prayer: ‘Doctor, I wish you could hear me … we haven’t got much time …’

  Then there was a cry from the far end of the cathedral, and several hands pointed up at the giant windows. Something was seeping up the outside of the stained glass. Something thick and dark; something that moved like liquid but in the wrong direction.

  Heads turned and prayers hushed. No one moved. Fear swept through the congregation as the moonlight dimmed.

  ‘As if these people haven’t been through enough,’ Graham said, agonised.

  ‘We should go and find the Doctor,’ Ryan said.

  A great heavy crashing sound echoed around the cathedral as the police closed the giant wooden doors, barring them firmly.

  ‘Too late,’ said Graham.

  The starfish were pouring in at the window, and Albert was starting to shake in his chair. ‘Look!’ he gasped, holding out his arms. ‘They’re turning black! The blood is rotting in my veins!’ He leaped up, the saucepan falling from his head, his hair springing into the characteristic Einstein look.

  Mileva rushed back to him. ‘Albert!’

  ‘Stay calm,’ ordered the Doctor.

  Yaz, at the window, wrinkled her nose. ‘What’s that smell?’ Seeping up the outside of the walls was the same black shadow that had followed them down the street. Only now it was easier to see. ‘Blood! Doctor, the street outside is covered in blood! And it’s coming up the walls!’

  ‘Albert, please put this back on,’ urged Mileva, holding out the saucepan, but he recoiled.

  ‘Get away from me! You’re behind all this, I know! You poisoned me! You set the spider on me!’

  ‘Alllberrrtt!’ A grinding, resonant voice came from the recesses of the hall, and the giant Mileva glided forward, arms reaching out as they had in the street earlier. ‘Alllberrtt, come to meee!’

  ‘Get away!’ screamed Albert. ‘Don’t touch me!’

  Another figure appeared from behind Mileva. ‘Alllberrtt …’

  ‘It looks like Michele Besso,’ Mileva said, frightened. ‘He’s Albert’s best friend.’

  Albert backed away, holding out his hands as protection.

  ‘Einstein thinks everyone’s against him.’ The Doctor grabbed the sonic and aimed it at the apparitions but nothing happened. ‘I can’t stop them – any of them!’

  ‘What have you done to my son, Serbian witch?’ hissed a new voice from the shadows.

  ‘That sounds like Pauline.’ Mileva turned ghostly pale. ‘Albert’s mother.’

  All sound had ceased in the cathedral. Everyone who was still conscious was looking at the windows which lined three sides of the building. Outside was dark, but it was still possible to discern the unknown liquid sliding up every single pane; climbing, climbing.

  There was a tiny sound, high up, the tink of cracking glass. Then another, and another. Tink-tink-tink … the splintering came from every side as the small windows began to give way.

  ‘What’s happening?’ asked Graham apprehensively.

  ‘Too dark to see all the way up there,’ said Ryan, squinting. He sniffed. ‘What’s that, though? That smell. Sort of … metallic. Reminds me of …’

  ‘Blood,’ said Graham. ‘It smells like blood.’

  They looked at each other. Then, in unison, their gazes returned to the darkness above and the oncoming horror.

  The figure of Pauline Einstein swelled as she approached, swallowing up the other two ghostly figures, absorbing them into her, thickening and growing with each step. Her face was a grotesque approximation of humanity; its distorted features pulled into a pleading expression. Her voice was an unpleasant whine. ‘Come home, Alberrrt.’ Yaz clapped her hands over her ears. ‘Come home and marry a nice simple girl … this one is not worthy of you … she is so … unmusical …’

  Mileva stepped in front of the apparition, ignoring the Doctor’s warning shout. ‘You shall not have him back!’ she shouted up. ‘We are to be happy, you hear me? Leave him alone!’

  The giant head turned towards her and the eyes blazed dark fire. ‘You and your bastard child …’ it hissed.

  Mileva rocked on her feet, shocked. ‘Do not call her that,’ she said, but her voice was weakening. ‘Her name is Lieserl! And she was no one’s fault!’

  ‘Liar!’ the apparition roared.

  Blood poured over the windowsill and began to stream across the floor. Yaz leapt back, away from the box of starfish. ‘Doctor! Doctor, do something!’

  ‘Albert!’ The Doctor ran to Einstein, cowering against the wall. ‘Albert, you can stop this! You have to fight back!’

  ‘No,’ said Albert, his hands over his face. ‘No, no, no, no.’

  ‘What do you love most in the world?’ the Doctor persisted. ‘Is it your work? Or is it that magnificent woman over there, fighting for you, willing to give up her life for you? The woman you want to marry, the one who’s proved she’s worth it, over and over? Are you going to let her die because of you, Albert? Are you?’

  On the other side of the room, the apparition became a swelling, billowing mass of dark anger, enveloping Mileva within it. She screamed.

  Einstein’s head jerked up at the sound. He still looked terrified, but now the light in his eyes burned steadily.

  He stood up.

  The blood oozed its painfully slow way down the inside of the cathedral walls, visible as a dark sticky fluid as it reached the edge of the pools of light cast by the thick candles. More and more of it poured in at the top of the windows every minute. Those families who still occupied spaces near the outer walls hurried inwards, to the already packed mass of people. Terror grew. Whispers and stifled cries as people tripped and fell on each other filtered through the air. Candles flickered and died, and darkness closed in.

  ‘Graham.’ It was Marthe, close by. ‘Listen. Johanna is breathing again. I don’t know how or why, but … listen.’

  Graham bent down. She was right. Johanna’s breath was no longer catching in her throat. And although it was hard to tell in the dim light, her lips looked a little less blue.

  ‘Do you think …?’ Marthe hardly dared finish the question.

  Graham squeezed her hand. ‘I told you not to give up hope.’

  His reassuring smile faded as he turned to see the thick sticky liquid start to pool on the floor.

  Yaz, pressed into a corner as the blood covered more and more of the floor, watched Einstein walk across to the whirling maelstrom that surrounded Mileva and reach into it. The smoke drew back from him, as if his touch were toxic. In the cloud, the face of Pauline Einstein could still be seen, twisted with anger.

  Mileva choked, ‘Albert?’

  ‘It’s me,’ he said. ‘Help me.’

  ‘Yes!’ she said. ‘Of course, yes, yes! Always.’

  He took both her hands. Above them, the apparition hesitated. The blood too held back its boiling advance.

  ‘Go on, Albert,’ the Doctor urged him. ‘Talk to Mileva. About the two of you.’

  ‘Dollie,’ said Einstein. ‘My darling Dollie. All this time, we have battled together, haven’t we? Even when I thought you didn’t love me, and you thought I didn’t love you.’

  Mileva gave a little laugh. ‘So many letters of apology from my sweet Johnnie.’

  ‘She is a bad choice,’ the voice of Pauline whined.

  Albert shook his head, not taking his eyes from Mileva for a moment. ‘No,’ he said, ‘she is the best choice I could make. She understands me like no one else. Like you never did.’

  The apparition’s mouth opened in horror, but no sound came out. Smoke began to evaporate from its limbs.

  ‘The only girl in the class.’ Albert smiled warmly at Mileva. ‘How lucky I was! To find someone with such a brilliant mind to work alongside, and then to find there was more than that.’

  Tears sprang to Mileva’s eyes. ‘So much more.’

  ‘The ghosts are shrinking!’ the Doctor called. ‘You’re doing it, Albert!’

  Yaz breathed a shaky sigh of relief as the blood receded across the floor, thinning and evaporating. The apparition above them broke into pieces that flared briefly and burned out like ash from a bonfire.

  ‘I’m so sorry.’ Albert kissed his sweetheart’s hands. ‘I’ve caused you so much pain and worry. And I’ve put you in such danger. But you never gave up on me.’

  ‘I never would,’ said Mileva softly.

  Albert stepped forward and pulled her close to him. The final fragments of the ghostly mother vanished into the air, and the floor was clean again.

  The tide of blood had reached the floor of the cathedral, but now, for the first time, it had slowed.

  ‘What’s it waiting for?’ Ryan murmured.

  As they watched, the liquid thinned and became blurry, like mist on a mirror. Ryan rubbed his eyes. ‘Is it – disappearing?’

  Within seconds, it was as though the blood had never been. Relief swept through the congregation.

  And Johanna opened her eyes.

  Back in the Rathaus, silence hung thickly until the Doctor strode over to the couple and said, ‘Albert, that was some serious strength of character there. You’ve done the hard bit, but we’ve still got to draw in all these starfish.’