Malus by Barry Boyd Bryson

The Door Simple, Quiet, and a great danger to everything near it. Three men discover its location and go missing. Sir Drake Lucas, joined by Pearl Gentry, August Cannon, and others discover they have disappeared and begin the search to find those who are lost. In a faraway land, they are joined by Cronan as they head to the door and enter the deep cave behind it. In its bowels, as their own lives become endangered, they attempt to escape, dividing into two parties trying desperately to stay alive. Cronan leads his followers into a beautiful environment that has a pending danger as Drake leads those at his side through a devastating landscape of volcanoes to find a lady who may help them survive. Yet, when she is found, there is another who informs Drake of an even greater danger. Malus, the truest embodiment of evil, has now put all things at risk of total annihilation. Only these few have any chance of preventing him from accomplishing his evil plans. With only so much time before the decimation of all things, Drake and Cronan lead the others towards an unknown fate, both aware that should they not be successful not only will they all die but everything that exists now will forever be gone.