The summer I was fifteen, she was happiest of all. I didn’t understand why, until afterwards. She waited till the last night of our holiday before she walked into the water.

Up until that night Dina was a sparky little scrap of contrariness and mischief, always ready to explode into her high bubbling giggle and always able to pull you in too. Afterwards, the doctors warned us to watch her for “emotional consequences”—these days she would have been shot straight into therapy, probably we all would, but this was the eighties, and this country still thought therapy was for rich people who needed a good kick up the arse. We watched—we were good at that; at first we watched 24/7, took turns sitting by Dina’s bed while she twitched and murmured in her sleep—but she didn’t seem to be in any worse shape than me or Geri, and she definitely looked a lot better off than our father. She sucked her thumb, cried a lot. Over a long while she went back to normal, as far as we could see. The day she woke me by shoving a wet facecloth down my back and running away screaming with laughter, Geri lit a candle to the Blessed Virgin, in thanksgiving that Dina was back.

I lit one too. I held on to the positive as hard as I could and told myself I believed it. But I knew: a night like that one doesn’t just disappear. I was right. That night burrowed deep inside Dina’s softest spot and stayed curled up, biding its time, for years. When it had swollen fat enough, it stirred, woke up and ate its way back to the surface.

We had never left Dina on her own during an episode. Occasionally she somehow got sidetracked before she reached my place or Geri’s; she had come to us bruised, coked off her face, once with an inch-wide clump of hair pulled out by the roots. Every time, Geri and I tried to find out what had happened, but we never expected her to tell us.

I thought about ringing in sick. I almost did it; I had the phone in my hand, ready to dial the squad room and tell them I had picked up a nasty dose of gastric flu from my niece and someone else would have to take on this case till I could step away from the bathroom. It wasn’t the instant career nosedive that stopped me, regardless of what everyone I know would have thought. It was the picture of Pat and Jenny Spain, fighting to the death alone because they believed we had abandoned them. I couldn’t find a way to live with making that the truth.

At a few minutes to four I went into my bedroom, switched my mobile to silent and watched the screen till it lit up with Richie’s name. More nothing; he was starting to sound sleepy. I said, “If there’s no action by five, you can start winding it up. Tell Whatshisname and the other floaters to go get some kip and report back in at noon. You can manage another few hours with no sleep, am I right?”