“You seem to know your way around here pretty well,” Bolivar said as we went through a locked door marked “Private” and along a dank corridor.

“When I bought the tickets this afternoon I let myself in and ran a quick survey. Here we are.”

I let the lads disconnect the burglar alarms themselves, good practice, and was chuffed to see that they needed no instruction. They even put a few drops of friction-freer in the tracks before slipping the window silently open. We gazed out into the night, at the dark form of a building a good five meters away.

“Is that it?“ Bolivar asked.

“If it is—how do we get there?” James said.

“It is—and this is how.” I slipped the gunlike object from my inside pocket and held it up by the looped and heavy handle. “It has no name since I designed and made it myself. When the trigger is pulled this projectile—shaped like a tiny plumber’s friend—is hurled forth with great velocity. It trails behind a thin strand of almost-unbreakable monomolecular filament. What happens then, you might ask, and I will be happy to tell. The shock of firing switches on a massive-charge battery in the projectile that expends all of its power in fifteen seconds. But during that time a magnetic field is created here on the projectile’s tip that has enough gauss to hold up a thousand-kilo load. Simple, isn’t it?”

“Are you sure you’re not simple, Dad?” Boliver asked, worried. “How can you be sure of hitting a piece of steel in the dark with that thing?’

“For two reasons, ohh scoffing son. I discovered earlier today that each story of that building has a steel cornice over a steel beam. Secondly, with a magnetic field that strong it is hard to keep this thing away from any steel or iron. It turns as it goes and seeks its own nesting place.