Cornucopia

Amber has made a deal with the devil.
To protect her incubus boyfriend, Irix, from the angels, Amber has agreed to journey to Hel and assist the humans there with their failing agricultural program. It's a project the botany major and half-elf/half-succubus would normally love, but the elves are stickers for genetic purity and consider her an abomination. Once in Hel, Amber must avoid the elves who would killer her, steer clear of demons who would love to add her to their collections, and somehow manage to create a Garden of Eden out of an arid desert. Human lives depend on her skills, and Irix's continued freedom depends on her honoring her contract with Satan.