‘I’ve been thinking about it all night,’ Lolly said, first thing. They were side by side in the kitchen: Harper was stirring porridge; Lolly was stewing apples with brown sugar and cinnamon for putting on top. ‘My grandfather’s family, especially Molly and Mae. I’ve heard you can look people up on a website called Ancestors-something. Would that be any use for your project?’

‘You need wi-fi for that,’ Harper replied.

‘Well,’ Lolly sniffed, and had a look about her that Harper hadn’t seen before. ‘Angus next door has it. We’ll ask him after breakfast.’

‘But you don’t like Angus. You called him annoying.’

‘I’ve never said that. Goodness. I can put up with him for your project.’

Lolly took the apples off the stove and spooned them into a bowl. There was no need to go over to see Angus when his wi-fi worked in her bedroom, but Harper couldn’t tell Lolly that.

After breakfast, Lolly said, ‘Nature calls!’ and went to the bathroom. When she came out her hair was smoother, she smelled flowery. ‘Ready?’ she said.

It was obvious by the way Angus smiled at Lolly when he opened the door, and the casual way Lolly walked into his flat, that Harper had missed something: Angus and Lolly were friends.

The flat mirrored Lolly’s in shape and size but not in decoration. Angus had a large fish tank on his kitchen bench, with lots of neon tetras darting around in it. There was a soft grey carpet in every room and down the hall, and the walls were all whitish, with paintings in frames of different sizes and colours. Harper was drawn to a bookcase that filled a wall from ceiling to floor. There was a ladder on a rail for reaching the top shelf.

Angus started up his computer, which sat on an antique desk in the same place as Lolly’s round dining table. He told her to use his account for searching ancestors. Harper had to bite her lip when he said his password: Jack1989. Angus seemed excited by her project and started to talk rapidly about Spanish flu, which he called the forgotten pandemic, until Lolly shut him up and said they should let Harper get on with it.

Lolly and Angus took coffees to his balcony. As Lolly closed the glass sliding doors, Harper caught her eye and smiled. Lolly frowned, which made Harper giggle. As she got started, she could hear them talking about birds.

There were lots of Lambs on the ancestors website. With some extra dates and facts that Lolly had remembered over breakfast, Harper found the right family tree. Like the one she’d hastily made for school last year, it had missing branches. This time it was Harper, Liz, Lolly and Lolly’s parents who were missing.

Molly and Mae’s birth and death years were there, 1901–1919. There was a birth date for Edward, Lolly’s grandfather, but no death date. Harper guessed that whoever had made the tree hadn’t known. The older brother’s name was Tobias Lamb; all the other branches of the tree came from him.

There were photographs next to some of the names. One of them was unmistakably of Molly and Mae as little girls, with their brother Edward and their other brother Tobias.

As Harper clicked one picture after another, hairstyles and clothing changed, poses relaxed and soon the photos became colour. A Christmas lunch with everyone in a paper hat. Men in stiff shirts, women in dresses cinched at the waist. Men with beards and women in short skirts, sitting on cars, saturated colours.

She found a boy called Francis Lamb. He wore a wide school hat with the Riverlark emblem: the tall steeple from the main building held inside a flourish of river. Francis Lamb was born in 1972, the same year as Harper’s mum. But Liz had gone to a bigger, nearby school. It was strange to think of Lamb families living so close but not knowing each other. Then again, before this year, Harper hadn’t known Lolly very well. That was hard to imagine now too.

After Francis, the background in the photos changed. Nothing looked like Melbourne any more. When she dug deeper, it seemed everyone had scattered: some to Adelaide, some to Perth. Lolly might be the only one of those Lamb relatives left in Melbourne and she wasn’t even on the tree.

Angus came inside to make more coffee. He put a large glass of his homemade lemonade next to Harper on his way back to the balcony. She sipped it and winced. It was the sourest thing she’d ever tasted. And there was so much of it. Harper forgot the Lambs and focused on this new problem: she’d have to pour it somewhere so that Angus wouldn’t be offended. So while Angus and Lolly were pointing out things to each other from his balcony, Harper snuck up the hallway to the bathroom.

She opened the door on the right but it was a cupboard, like Lolly had on the left. The bathroom was on the other side. She locked the door and tried again to sip the lemonade but it made one eye close and her mouth prickle. Guiltily she poured it into the basin and ran the tap.

Lolly was calling her. In a panic, she put the glass down by the side of the laundry basket and said ‘Coming!’

‘I’ve got a gardening job to get to,’ Lolly said. ‘And the dogs need a walk. But Angus says you can come back any time to do work on your school project. Find anything interesting?’

‘I found a boy called Francis Lamb who went to Riverlark. He was born the same year as Mum. 1972.’

‘Aren’t families strange, sometimes?’ said Lolly. ‘Relatives I never knew about. Would the school keep records that far back?’

Angus took his glasses off, and cleaned them with a handkerchief.

‘I suppose you’ve already looked through the Riverlark archives?’ he asked Harper.

Harper tried to look as if she knew what that meant but Angus must have seen through it.

‘An archive is a collection of important historical documents.’

Harper thought of the door in the library that hardly seemed like the entrance to somewhere else at all, but more like a part of the wall that nobody noticed. That was why the library was L-shaped, because of whatever was in there. Maybe it wasn’t props or sports equipment, but an archive. She’d have to find a way to get in there.

Harper took the dogs for a walk by the river. Annie and Murph were on leads and walked calmly beside her; Lolly never used one for Hector, he was always free range. Everything around her was familiar, but in her head she was lost. She’d pulled at the thread of Molly and Mae because they were Will’s friends and they’d turned out to be her own family. What about what Will had asked of her? He wanted help. What was she supposed to do next?

But the problem was going to have to wait because in less than twenty-four hours her friends were arriving for her party. There were two worries about that: first, that the last time she’d seen Cleo she’d walked off in a huff. Second, that she hadn’t told Lolly yet.