Across from him, a boy of about seventeen was staring quietly into space, his eyes half-open at the edge of boredom and sleep. When Alex had been about the boy’s age, he’d been deciding whether to go into the Navy or apply for upper university. He’d been dating Kerry Trautwine even though Mr. Trautwine was a religious zealot who hated him for not belonging to the right sect. He’d spent his nights playing battle simulations with Amal Shah and Korol Nadkarni.

This boy across from him was traveling the same corridors that Alex had, eating at some of the same restaurants, thinking about sex in likely more or less the same terms, but he also lived in a different universe. Alex tried to imagine what it would have been like to include travel to an alien planet in among his options at seventeen. Would he have still enlisted? Would he have met Talissa?

A gentle, mechanical voice announced their arrival at the Aterpol terminal. The boy’s eyes opened, roused back to full consciousness, and he shot a distrustful look at Alex. The deceleration pushed Alex’s back, feeling almost like a long attitude burn. Almost but not quite.

Aterpol was the downtown of Londres Nova, the only station with connections to all of the neighborhoods that made up the city. The vaulted ceilings curved over the common areas, the access doors along the walls double-sealed to keep air from leaking into the evacuated tubes. The terminal itself opened into a wide public park with real trees rising from the soil into the artificial twilight. Benches made to look like wood and iron stood scattered along the winding paths, and a pond filled the air with the smells of algae and moisture. The reassuring breeze-murmur of the air recyclers passed under everything like a constant and eternal prayer. Windows rose up along the walls, light streaming out of them or not. The rooms that looked out over Alex as he walked were businesses and apartments, restaurants and maintenance halls.

Alex crossed the park to the farther gates, where the local tubes ran to the other neighborhoods. Innis Shallow, where Bobbie lived, didn’t have the best reputation. The worst that Mars had to offer wasn’t as bad as an iffy sector on Ceres Station, though, and regardless anyone who took on Bobbie was either suicidal or had an army behind them.

At the Innis Shallow station, Alex shrugged into his jacket and went on foot. There were carts for rent and a girl of no more than fourteen with a scavenged rickshaw calling on the corner. It was a short walk, though, and Alex was dreading the conversation at the end of it.