'Why is she lying down?' Charlie whispered.

'Because she's a Minus, Charlie. Surely you know what a minus looks like … Like that …' Mr Wonka drew a horizontal line in the air with his finger.

The Elevator glided close. The ghostly shadow of Grandma Georgina's face was no more than a yard away now. Charlie reached out through the door to touch her but there was nothing there to touch. His hand went right through her skin. 'Grandma!' he gasped. She began to drift away.

'Stand back!' ordered Mr Wonka, and suddenly, from some secret place inside his coat-tails he whisked out a spray-gun. It was one of those old-fashioned things people used to use for spraying fly-spray around the room before aerosols came along. He aimed the spray-gun straight at the shadow of Grandma Georgina and he pumped the handle hard ONCE … TWICE … THREE TIMES! Each time, a fine black spray spurted out from the nozzle of the gun. Instantly, Grandma Georgina disappeared.

'A bull's eye!' cried Mr Wonka, jumping up and down with excitement. 'I got her with both barrels! I plussed her good and proper! That's Vita-Wonk for you!'

'Where's she gone?' Charlie asked.

'Back where she came from, of course! To the factory! She's a Minus no longer, my boy! She's a one hundred per cent red-blooded Plus! Come along now! Let's get out of here quickly before the Gnoolies find us!' Mr Wonka jabbed a button. The doors closed and the Great Glass Elevator shot upwards for home.

'Sit down and strap yourself in again, Charlie!' said Mr Wonka. 'We're going flat out this time!'

The Elevator roared and rocketed up toward the surface of the Earth. Mr Wonka and Charlie sat side by side on their little jump-seats, strapped in tight. Mr Wonka started tucking the spray-gun back into that enormous pocket somewhere in his coat-tails. 'It's such a pity one has to use a clumsy old thing like this,' he said. 'But there's simply no other way of doing it. Ideally, of course, one would measure out exactly the right number of drops into a teaspoon and feed it carefully into the mouth. But it's impossible to feed anything into a Minus. It's like trying to feed one's own shadow. That's why I've got to use a spray-gun. Spray 'em all over, my boy! That's the only way!'

'It worked fine, though, didn't it?' Charlie said.

'Oh, it worked all right, Charlie! It worked beautifully! All I'm saying is that there's bound to be a slight overdose …'

'I don't quite know what you mean, Mr Wonka.'

'My dear boy, if it only takes four drops of Vita-Wonk to turn a young Oompa-Loompa into an old man …' Mr Wonka lifted his hands and let them fall limply on to his lap.

'You mean Grandma may have got too much?' asked Charlie, turning slightly pale. 'I'm afraid that's putting it rather mildly,' said Mr Wonka.

'But … but why did you give her such a lot of it, then?' said Charlie, getting more and more worried. 'Why did you spray her three times? She must have got pints and pints of it!'

'Gallons!' cried Mr Wonka, slapping his thighs. 'Gallons and gallons! But don't let a little thing like that bother you, my dear Charlie! The important part of it is we've got her back! She's a Minus no longer! She's a lovely Plus!

'We return in triumph, Charlie!' cried Mr Wonka as the Great Glass Elevator began to slow down. 'Once more your dear family will all be together again!'

The Elevator stopped. The doors slid open. And there was the Chocolate Room and the chocolate river and the Oompa-Loompas and in the middle of it all the great bed belonging to the old grandparents. 'Charlie!' said Grandpa Joe, rushing forward. 'Thank heavens you're back!' Charlie hugged him. Then he hugged his mother and his father. 'Is she here?' he said. 'Grandma Georgina?'

Nobody answered. Nobody did anything except Grandpa Joe, who pointed to the bed. He pointed but he didn't look where he was pointing. None of them looked at the bed – except Charlie. He walked past them all to get a better view, and he saw at one end the two babies, Grandma Josephine and Grandpa George, both tucked in and sleeping peacefully. At the other end …

'Don't be alarmed,' said Mr Wonka, running up and placing a hand on Charlie's arm. 'She's bound to be just a teeny bit over-plussed. I warned you about that.'

'What have you done to her?' cried Mrs Bucket. 'My poor old mother!'

Propped up against the pillows at the other end of the bed was the most extraordinary-looking thing Charlie had ever seen! Was it some ancient fossil? It couldn't be that because it was moving slightly! And now it was making sounds! Croaking sounds – the kind of sounds a very old frog might make if it knew a few words. 'Well, well, well,' it croaked. 'If it isn't dear Charlie.'

'Grandma!' cried Charlie. 'Grandma Georgina! Oh … Oh … Oh!'

Her tiny face was like a pickled walnut. There were such masses of creases and wrinkles that the mouth and eyes and even the nose were sunken almost out of sight. Her hair was pure white and her hands, which were resting on top of the blanket, were just little lumps of wrinkly skin.

The presence of this ancient creature seemed to have terrified not only Mr and Mrs Bucket, but Grandpa Joe as well. They stood well back, away from the bed. Mr Wonka, on the other hand, was as happy as ever. 'My dear lady!' he cried, advancing to the edge of the bed and clasping one of those tiny wrinkled hands in both of his. 'Welcome home! And how are you feeling on this bright and glorious day?'

'Not too bad,' croaked Grandma Georgina. 'Not too bad at all … considering my age.'

'Good for you!' said Mr Wonka. 'Atta girl! All we've got to do now is find out exactly how old you are! Then we shall be able to take further action!'

'You're taking no further action around here,' said Mrs Bucket, tight-lipped. 'You've done enough damage already!'

'But my dear old muddleheaded mugwump,' said Mr Wonka, turning to Mrs Bucket. 'What does it matter that the old girl has become a trifle too old? We can put that right in a jiffy! Have you forgotten Wonka-Vite and how every tablet makes you twenty years younger? We shall bring her back! We shall transform her into a blossoming blushing maiden in the twink of an eye!'

'What good is that when her husband's not even out of his nappies yet?' wailed Mrs Bucket, pointing a finger at the one-year-old Grandpa George, so peacefully sleeping.

'Madam,' said Mr Wonka, 'let us do one thing at a time …'

'I forbid you to give her that beastly Wonka-Vite!' said Mrs Bucket. 'You'll turn her into a Minus again just as sure as I'm standing here!'

'I don't want to be a Minus!' croaked Grandma Georgina. 'If I ever have to go back to that beastly Minusland again, the Gnoolies will knickle me!'

'Fear not!' said Mr Wonka. 'This time I myself will supervise the giving of the medicine. I shall personally see to it that you get the correct dosage. But listen very carefully now! I cannot work out how many pills to give you until I know exactly how old you are! That's obvious, isn't it?'

'It is not obvious at all,' said Mrs Bucket. 'Why can't you give her one pill at a time and play it safe?'

'Impossible, madam. In very serious cases such as this one, Wonka-Vite doesn't work at all when given in small doses. You've got to throw everything at her in one go. You've got to hit her with it hard. A single pill wouldn't even begin to shift her. She's too far gone for that. It's all or nothing.'