An Aztec god is threatening the world as we know it. And how? By hijacking Silicon Valley technology, of course.
"He's using semiconductors to effect his evil plan," Keenan explained.
The heroine is Sierra Carter, a recently fired public-relations executive who finds her life suddenly altered as she's chosen by the good god to battle evil and restore the weaponized science.
She's joined by a band of friends and helpers, like anthropomorphic trickster el coyote and semi-humanoid schemer mannegishi, both characters of Native American mythology who have a place, according to the story, in combating monsters.
The motley crew's adventures primarily occur in Mountain View and Sunnyvale, providing local readers with plenty of physical context.
"There are various sites around Silicon Valley that people will recognize," Keenan said, including Lion & Compass restaurant and the Sunnyvale police station.
The heroine and her team, do, however, venture as far as Mono Lake, the Santa Cruz Mountains and Half Moon Bay, locales that open the dialogue for the story's underlying environmental issues.
"She's outdoorsy, she loves nature, ... she's very concerned about the environment," Keenan remarked of her protagonist.
In her next book, Keenan will take Sierra Carter and her crew to Hawaii to tackle the environmental concern of the Pacific Garbage Patch.
Keenan, who worked in public relations in Silicon Valley for many years, began writing after her freelance work came to a lull.
"Writing was the thing I really enjoyed the most," she said.
Keenan often wondered why most fantasies are set in "pre-industrial, pseudo-European" cultures, the kind where everyone is cloaked in black and lives in cobblestone castles.
For fantasy buffs, Keenan's use of Native American myths, Mayan archetypes and Voodoo traditions may prove a welcome change from the ubiquitous blood-sucker-battles-wolfman routine.
"There's not a single vampire in sight," Keenan said.
"The Americas have thousands of rich traditions," she added of the folklore that provided her creative fodder.
Though initially unsure if she could pull off a modern-day fantasy that borrowed from American legend, Keenan remembered telling herself, "Let's just see if it can be done."
Keenan's knowledge of Southwestern and Native American cultures, primarily born from childhood experiences with an archeologist mother, delivered much of her inspiration, though she supplemented this education with plenty of reading, too.
Keenan was aware, however, of the hundreds of stories and interpretations on the mythology. Even tequila brands want their own spin on the old stories for marketing purposes, so she tried not to be too serious in her version.
"I intended it to be a fun read," she said.
What: K.D. Keenan will read an excerpt of "The Obsidian Mirror"
When: 2 p.m., Saturday, June 28
Where: Kepler's Books, 1010 El Camino Real, Menlo Park
Cost: Free, catered with wine and food
Information: keplers.com/event/kd-keenan or contact Pam Grange at 650-324-4321