He ran down the path with Bets. Fatty leaned out of the window of his den and yelled, ‘Oy! You’re a fine detective! You’ve forgotten the letter!’

‘So I have!’ said Pip and tore back for it. Fatty dropped it down. Pip caught it and ran off again. He and Bets tore to the pillar-box at the corner and were just in time to catch the postman emptying the letters from the inside.

‘One more!’ said Pip. ‘Thanks, postman! Come on, Bets. We’ll try out your book-idea as soon as we get home.’

Bets flew to find the book that Gladys had lent her, as soon as she got home. She found it at once. It was an old school prize, called The Little Saint. Bets had been rather bored with it. ‘The Little Saint’ had been a girl much too good to be true. Bets preferred to read about naughty, lively children.

She wrapped the book up carefully, and then went down to say good-night to her mother. Mrs. Hilton was reading in the drawing-room.

‘Come to say good-night, Bets?’ she said, looking at the clock. ‘Did you have a nice time at Fatty’s?’

‘Yes! We played his new game, Woo-hoo-colly-wobbles,’ said Bets. ‘It was fun.’

‘I expect it was noisy and ridiculous if it was anything to do with Frederick,’ said her mother. ‘What’s that you’ve got, Bets?’

‘Oh Mother, it’s a book that Gladys lent me,’ said Bets. ‘I was going to ask Mrs. Moon her address so that I could send it to her. Could I have a stamp, Mother!’

‘You don’t need to ask Mrs. Moon,’ said her mother. ‘I’ll see that Gladys gets it.’

‘Oh,’ said Bets. ‘Well - I’ll just put her address on it. I’ve written her name. What’s her address, Mother?’

‘I’ll write it,’ said Mrs. Hilton. ‘Now don’t stand there putting off time, Bets. Go up to bed. Leave the parcel here.’

‘Oh, do let me just write the address,’ said poor Bets, feeling that her wonderful idea was coming to nothing, and that it wasn’t fair. ‘I feel like writing, Mother.’

‘Well, it must be for the first time in your life then!’ said Mrs. Hilton. ‘You’ve always said how much you hate writing before. Go up to bed, Bets, now.’

Bets had to go. She left the book on the table by her mother, feeling rather doleful. But perhaps Pip would see the address later on in the evening, if her mother wrote it on the parcel.

Pip said he’d keep an eye open. Anyway, what did it matter? His own letter would come in the morning and they’d soon find out the right address.

He saw the book on the table when he went down ready for dinner, cleaned and brushed. He read the name on the wrapping-paper... but there was no address there yet.

‘Shall I write Gladys’s address for you, Mother?’ he asked politely. ‘Just to save you time.’

‘I can’t imagine why you and Bets are so anxious to do a little writing tonight!’ said Mrs. Hilton, looking up from her book. ‘No, Pip. I can’t be bothered to look up the address now, and I can’t remember it off-hand. Leave it.’

So it had to be left. Pip was glad to think his letter was coming in the morning. He was sure that had been a better idea than Bets’!

Pip was down early next morning, waiting for the postman. He took all the letters out of the box and put them by his mother’s plate. His own was there, addressed in Fatty’s disguised handwriting.

‘There’s a letter for Gladys, Mother,’ said Pip, at breakfast-time. ‘We’ll have to re-address it.’

‘My dear boy, you don’t need to tell me that!’ said Mrs. Hilton.

‘Did you put the address on my parcel?’ asked Bets, attacking her boiled egg hungrily.

‘No. I couldn’t remember it last night,’ said Mrs. Hilton, reading her letters.

‘Shall Pip and I take the letters and the parcel to the post for you this morning?’ asked Bets, thinking this was really a very good idea.

‘If you like,’ said Mrs. Hilton. Bets winked at Pip. Now things would be easy! They could both see the address they wanted.

A telephone call came for Mrs. Hilton after breakfast, whilst the children were hanging about waiting to take the letters. Mrs. Moon answered it. She went in to Mrs. Hilton.

‘There’s a call for you, Mam,’ she said.

‘Who is it?’ asked Mrs. Hilton. Pip and Bets were most astonished to see Mrs. Moon winking and nodding mysteriously to their mother, but not saying any name. However, Mrs. Hilton seemed to understand all right. She got up and went to the telephone, shutting the door behind her so that the children could not follow without being noticed.

‘Well - who’s on the phone that Mother doesn’t want us to know about?’ said Pip, annoyed. ‘Did you see how mysterious Mrs. Moon was, Bets?’

‘Yes,’ said Bets. ‘Can’t we just open the door a bit and listen, Pip?’

‘No,’ said Pip. ‘We really can’t. Not if Mother doesn’t want us to hear.’

Their mother came back after a minute or two. She didn’t say who had telephoned to her and the children didn’t dare to ask.

‘Shall we go to the post-office now?’ said Pip, at last. ‘We’re ready.’

‘Yes. There are the letters over there,’ said Mrs. Hilton.

‘What about my parcel for Gladys?’ said Bets.

‘Oh, that doesn’t need to go - nor the letter for her,’ said Mrs. Hilton. ‘Somebody’s going to see her today and he will take them. That will save putting a stamp on the parcel.’

‘Who’s going to see Gladys?’ asked Pip. ‘Can we go too? I’d like to see Gladys again.’

‘Well, you can’t,’ said Mrs. Hilton. ‘And please don’t start trying to find out things, Pip, because, as I’ve already told you, this is nothing whatever to do with you. You can take the other letters to the post for me. Go now and you will catch the ten o’clock post.’

Pip and Bets went off rather sulkily. Bets was near tears. ‘It’s too bad, Pip,’ she said, when they got out-of-doors, ‘we had such good ideas - and now they’re no use at all!’

‘We’ll post the letters and then go up and see Fatty,’ said Pip gloomily. ‘I expect he’ll think we ought to have done better. He always thinks he can do things so marvellously.’

‘Well, so he can,’ said Bets loyally. ‘Let me post the letters, Pip. Here’s the post office.’

‘Here you are then. What a baby you are to like posting letters still!’ said Pip. Bets slipped them into the letter-box and they turned to go up to Fatty’s house. He was at home, reading a new detective book.

‘Our ideas weren’t any good,’ said Pip. He told Fatty what had happened. Fatty was unexpectedly sympathetic.

‘That was hard luck,’ he said. ‘You both had jolly fine ideas, and it was only a bit of bad luck that stopped them having their reward. Now - who is it that is going to see Gladys today?’

‘Mother said it was a “he,” ’ said Pip. ‘She said, “Somebody’s going to see Gladys today, and he will take them!” ’

‘That’s easy then,’ said Fatty briskly. ‘He can only mean one person - and that’s old Clear-Orf! Well, now we know what to do.’

‘I don’t know,’ said Pip, still gloomy. ‘You always seem to know everything, Fatty.’

‘Brains, my dear fellow, brains!’ said Fatty. ‘Well, look here - if it’s Goon that’s going to see Gladys, we can wait about and follow him, can’t we? He’ll go on his bike, I expect - well, we can go on ours! Easy!’

Pip and Bets cheered up. The idea of stalking old Clear-Orf was a pleasing one. They would have the fun of doing that, and would find out too where Gladys lived. Yes, today looked much more exciting now.

‘You go and tell Larry and Daisy,’ said Fatty. ‘We shall have to keep a watch on old Goon’s house so that we know when he leaves. I vote we ask our mothers for food again, so that we can go off at any time and come back when we like.’

‘I’m going to buy Gladys some sweets,’ said Bets. ‘I like her.’

‘It would be a good idea if we all took her some little present,’ said Fatty thoughtfully. ‘Sort of show we were sorry for her and were on her side, so that she’ll be more willing to talk.’