The tree's heart beats faster. Its small mouths gather, forming one large maw. A long tongue unfurls and wraps around my wrist.

"Wait!" Abuelita shouts.

The blood falls from my finger.

Before it lands into the mouth, Abuelita catches it. "Fire-Snake, show respect. Release my granddaughter if you want your offering."

A breathy female voice hisses. "Is-s mine."

The tree's heart spasms. Branches thrash around us. The cacao fruit and leaves shrivel. As if split with an unseen axe, the trunk splinters apart. Bark peels away, and a snake-like woman crawls out of the wood. Red and orange scales shine beneath her flaming aura.

"Stay back." Abuelita stands between me and the goddess.

Fire-Snake's slender tail whips, a rattle at its tip. Eyes without pupils leer from her triangular face, the cold stare of a hunter stalking prey. Carved turquoise plugs hang from her earlobes, and a crown of torches blazes around her head. Her fanged mouth draws too wide for a human smile.

The tree releases me as it wilts.

Abuelita grabs the obsidian knife from me. Her long white braid lashes in a torrent of magic. She waves at the shrine's entrance, and the door crashes open. "Rodrigo, sound the alarm," she yells.

A bell clangs from the kitchen, the emergency chime on Rodrigo's spirit-house. It peals through the chamber, through flesh and spirit, to summon our allies.

Thick, dark liquid oozes down Fire-Snake's body. I can smell it--the delicious temptation of blood and chocolate mingled together. It's too much. My muscles tense, and I cry out. "'Lita, I can't...losing control."

Abuelita looks into my eyes. "You can. Fight it, mija."

Too late. My fangs lengthen. Hooked talons extend from my fingers. My hands swell to a bestial size, and my vision rims black with blood-frenzy. The monster inside me devours my sanity.

I shove Abuelita aside and lunge at Fire-Snake.

The serpent-goddess strikes me hard across the jaw.

My scream roars. The pain restores some of my sensibility. Reeling, I stagger away.

Flame surges around Fire-Snake. She shifts into a burning serpent form.

The protective wards and circles blink out.

"Por el poder de Santa Muerte!" Abuelita hurls a shining wave of magic from her fingers.

Fire-Snake dodges the blast. Her tail lashes around the cacao tree, and she drags it from its pot. Roots shred loose.

Soil and blood fleck my skin. I clutch my aching head and try to catch my breath.

Abuelita projects another wave of power, knocking Fire-Snake into the wall.

The tree keels over.

Fire-Snake flees to the open door. She bursts through and shatters the remaining hex shields. Gone.

The shrine falls silent and dark.