Keep Of Fire

Description for KEEP OF FIRE by Mark Anthony:

The Keep Of Fire

Travis Wilder has returned from the otherworld of Eldh, hoping to settle back into his humdrum  life in the mountains of contemporary Colorado. But he soon finds himself stalked by two shadowy organizations, each aware of his incredible journey and each determined to exploit it--whatever the cost to Travis...or to Eldh. Meanwhile, a terrifying new contagion is spreading like wildfire, a disease with no cure, which some are comparing to the Black Plague.

When the disease strikes his closest friend, Travis is drawn back to Eldh, where the same epidemic, known as the Burning Plague, is wreaking another kind of havoc. There, in a realm of gods and monsters, myths and runecraft, Travis and his former companion Grace Beckett--herself from Earth, but now living on Eldh--must solve the riddle of the plague. Where did it come from? What is its purpose? And how can it possibly be stopped...before it completely destroys two coexisting worlds: ancient Eldh and modern Earth.

This is #2 in The Last Rune Series.