The handle snapped on one of his bags, but he managed to catch it before the shopping tumbled out. He lugged everything to one of the benches that stood at intervals along the prom and sat down.

I stopped and leaned over the railings. My phone pinged but I ignored it and looked out to sea instead. There was no play of light on the water today; the surface was as flat and opaque as a slate, and it was difficult to believe in the complexities that lurked under its surface: the seething depths and the rough tug of tides; the bony shipwrecks and ropes of bladder wrack.

Grocery bags rustled behind me as the man rearranged his shopping. Further down the prom, the guitar music petered out and the girl began a new tune. She was quite good. Occasionally she’d throw in a lyric, then she’d stop and hum.

The bags stopped rustling. I waited for some other sound to betray his presence—a clearing of the throat, a sniff—but there was nothing. Had he gone? But I would have noticed the clip of his shoes on the pavement. I turned my head a fraction.

The man was sitting with his legs crossed and leaning on his knee to write or draw with a ballpoint pen. His face had altered: there was something intensely childlike about the way he glowered and worked his jaw whilst skimming the blue pen over the paper. I’d had him down as older than me when I spotted him from the bus window, but now he seemed younger. I wondered what he was sketching—the sea?—until he raised his head and narrowed his eyes at me. My cheeks went hot and I frowned. His stare was keenly observant but distant; sensitive to the lines, shapes, and structures of my posture, but unaware of me as me. When he noticed I was watching, it took him a while to register the shift in perception, and his smile, when it came, was shy.

“Sorry!” Reluctantly, he stuck the pen behind his ear and began to fold the drawing.

“No, it’s OK . . .” I wasn’t entirely sure that it was, but he looked at me long and hard and decided to take me at my word. He spread the paper on his knee again. It was one of those bags you get from a bakery, spotted with grease and crumbs.

“Are you sure you don’t mind?”

“I suppose . . .”

“And . . . would you mind facing out to sea again, and staying very still?”

I did as he asked, but this time I hardly noticed the sea itself. I itched to watch him watching me, but I kept my back turned and listened to the paper bag crinkling under the strokes of his pen. My phone rang—it was Dad’s ringtone—but I didn’t dare move. I could call him back later.

“OK, finished,” said the man.

“Can I see?”

“Oh God, please no.” He shook his head and dropped the paper into one of his shopping bags. “It’s only the beginnings of a sketch. It’s nothing.”