She nods, impressed, and puts down her phone. Ever since I agreed to go, I’ve been studying non-stop. I’ve memorised all the types of coral found in the Great Barrier Reef and can identify them by their photo as well as their defining characteristics. I know almost as much about staghorn corals as Millie does. I know all the fish to look out for, how to take pictures of them without scaring them away, and how to spot their eggs. I’ve absorbed so much knowledge that I would be able to fool Hugh – that is, if we were still talking. After our last conversation, I replaced my Instagram app with a Marine Biology dictionary so that I remember my real reason for Australia – finding the butterfly wrasse for Millie, and so that I would stop messaging Hugh. If I’m going to find the wrasse, I can’t afford any distractions. I also couldn’t think of a comeback, but that’s neither here nor there.

For the first time since graduating, my marine biology degree is proving useful. I’ve started feeling a thrum of excitement when I wake up in the morning. I’ve started humming when I take Murphy out for walks.

‘Stop smiling like that.’ Millie swats at me, giggling.

‘Like what?’

‘You’re smirking like you’re so proud of yourself for getting the answers to my questions right.’

I try to wipe the smile off my face.

‘I’m happy for you,’ Millie says, her voice dipping into sincerity. I know she means it, but I still can’t shake off the guilt I’m carrying for going on her dream trip without her.

‘I’ll be worried about you,’ I reply to Millie, my voice catching.

The day after I’ll arrive in Australia, a week and a half before Christmas, Millie’s scheduled for surgery. Surgery takes six to twelve hours and she’s in the hospital for two days afterwards. The procedure isn’t particularly risky, but I’m nervous. Millie’s kept her cool. She’s even scheduled a spray tan before she goes back to work so everyone will think she went to Australia. She doesn’t want to have to answer anyone’s questions or be on the receiving end of their pity.

‘I’ll be fine. It’s good to see you so . . . so happy.’

I glare at her. ‘It always comes back to my lack of happiness, doesn’t it? I’m fine. I’ve told you that.’

‘You know what I mean,’ Millie murmurs, flipping a page in her magazine. ‘You’re fine, but . . .’ She trails off, letting the words hang in the air with meaning.