“In humans, on the other hand,” the colonel continues with relish, “the candirú is like a tiny kamikaze with teeth. It’s attracted to blood and urine. It swims into an orifice—the urethra, the vagina, or the anus. It erects its spine and sucks blood. But then it can’t swim out. It can only go deeper, continuing to feast on blood and tissue till the hemorrhages kill the host.”

I can see them very clearly now. A thousand tiny snakelike shadows, coiling and untying beneath me, roiling the surface of the water with their hunger for blood.

The bridge continues to narrow. It can’t be more than three inches wide now—the sides of my feet protrude over its edges. I keep my weight centered, and try to keep my concentration equally fixed. But that’s nearly impossible as the colonel finishes his vivid warnings.

“And the pain, Jack! Think what it must be like to be eaten from the inside! They’re insatiable, indefatigable. Legend says that they can even swim up a urine stream. It’s unclear whether this is true, but I can tell you that natives on certain parts of the Orinoco don’t ever relieve themselves into the river. Of course, if you and P.J. were to fall into this pool, they wouldn’t have to resort to such extreme measures to get at you. You’d be coming right to their dinner table, so to speak.”

His words stoke my rising fear, twisting it tighter, so that I tremble and have to move my arms quickly just to stay on the beam. I can picture myself dying in the horrible way he describes. And P.J., too, right next to me.

“You may have noticed that the surface of the water is five feet beneath the floor,” the colonel drones on. “That’s for safety—I wouldn’t want any of the little devils to jump out when I come to visit them. But it also keeps anyone who falls into the pool from climbing out. The walls have been sanded down so that they’re smooth, to make sure there are no fingerholds. Once you drop in, all you can do is splash around, hip deep, and wait for them. Or you can try to drown yourself, which is surprisingly difficult. The body’s impulse to stay alive is remarkably strong, even with the certain knowledge that one would be far better off dead. Jack, if I can’t persuade you to reveal Kidah’s hiding place, perhaps someone else can. She’s been following this whole discussion. Shall I let her talk to you for a few moments?”