I walk up to the weathered wooden shack, peer through the dirt- and grime-crusted window, and scan the late-night diners. All distinctly human.

If my eyes weren’t practically tearing at the stench, I’d think the hydra wasn’t here.

Then I catch sight of the narrow staircase off to the right of the bar, leading to an upstairs dining room. Well, at least that will make cornering it easier.

As I push open the door, the combination of putrid eau de hydra and decades of fried-fish-filet residue is enough to make me nearly lose my heat-and-eat lasagna all over the sandy floor.

But I don’t have time for nausea. There’s a bloodthirsty monster prowling for a meal, and if I don’t stop it, no one will. I’m the only one who can see it.

“Anyone see a slithering nine-headed serpent pass this way?”

I snicker. I would love to see the reaction if I actually asked the question loud enough for anyone to hear.

Then again, this is San Francisco. They might not react at all.

Bypassing the drowsy bartender, I head for the staircase. Monsters generally prefer dark corners and back alleys—and, apparently, second-floor dining areas—which makes them occasionally harder to find but easier to attack. They’ll take any less-populated area that’s available, though, which is fine by me. The fewer witnesses to our fights, the better. The safer. The human world doesn’t need to know monsters walk among them. As long as I do my job right, they never will.

I’m up the stairs, three at a time, in five seconds flat. The instant I step out onto the second floor, I see it, cozying up to a trampy redhead doing her best impersonation of a low-class prostitute. Monsters have the worst taste in women.

I scan the room, checking for potential threats and exits. Besides the stairs behind me, there’s an emergency exit at the back. If I position myself behind the redhead, I’ll be able to intercept on either path.

As for threats, there’s a pair of mounted swordfish displayed on the wall and some framed pictures of deep-sea fishing boats that might hurt if used as projectiles. Nothing really to worry about.

Thankfully, the dining area is sparsely populated. Other than the hydra and its prey there is only a trio of drunken businessmen at the far end. Judging from their raucous volume and the disheveled state of their ties, odds are they’re probably pretty much oblivious to anything but the next round. If I do this right, they won’t notice a thing.

Straightening my back, I march over to the unlucky couple and tap the girl on the shoulder, making sure I’m centered between the stairs and the door.

“Can I help you?” Red snaps in a very nonsolicitous tone.

“Yes,” I reply. “You can leave.”