And his father has always wanted to see this bar, this strange bar where they only play one band (Led Zeppelin), and only serve one kind of wine (Australian Shiraz), and only have one thing to eat on the menu (truffle pasta).

For a moment Christian doesn’t see us standing in the pink glow of The One Bar’s doorway and I watch him, lost in the music. The song playing is the other side of Led Zeppelin, that reflective, folky side that was always so important to the band, Jimmy Page sounding as wistfully tender as Joni Mitchell on Blue. I can’t quite place the track. Something from Houses of the Holy? I used to know this stuff, I think, as I watch the sleek, well dressed young couples sipping their red wine and eating their truffle pasta.

Christian is the oldest person in the bar, and the scruffiest, and the only person who sits alone. He wears the leather jacket and jeans that he always wears these days.

And then he sees us, and his face lights up.

And he smiles, and we moved towards him, all of us smiling, and I feel happy and sad all at once because for those few moments as we cross the bar to Christian, it really feels like we are a family again.

‘We got lost!’ I say.

Marlo gazes around the bar, grasps the concept and, despite his worship of all things Japanese, finds it baffling.

‘Having a good time, kiddo?’ Christian asks him.

Marlo grunts an affirmative, not convinced by the bar’s central thesis.

‘But why would you want just one thing?’ he says, dipping his head to his phone as his father stares at him, his smile fading. I know what Christian is thinking, Why don’t you turn off the bloody phone for five minutes?

But he doesn’t say it. Christian is making an effort. When he sees Marlo these days – and it is much more sporadic than when Marlo was little, and we arranged his social life for him – Christian is constantly making an effort. Their relationship is more combative, more prickly than I would like, and it may get worse before it gets better. Despite the ten years since we parted, Christian has never considered himself an absent father, he was never going to embrace the cliché of the absent parent who overdoes the kindness. If anything, he is a far sterner father than when Marlo was little and they were spending their days together while I was out working.

And then Marlo’s face breaks into a smile. ‘This is Shibuya, right? We’re really close to Mandarake.’

Christian and I look blank, glance at each other for help.

‘It’s quite famous,’ Marlo says with infinite teenage patience. ‘Mandarake is the best place in the world to buy manga.’

‘Comics,’ Christian says.

‘No, Dad. Not comics. Manga.’

This is what Marlo lives for, this is where he looks for all the things that feed his soul. I remembered how we looked to America for our music, our films, our heroes – well, Marlo’s head is pointing in the opposite direction. Marlo looks East. It’s why my mum – ‘Why shouldn’t I spoil him?’ she asked me – shelled out for two tickets east for his sixteenth birthday.