The Midgardians and the Nine Realms

Book 1   Tessa along with her older brother Andrew and his friend Travis are normal teenagers from New York who crash through the floor of an abandoned mine while camping. They're found by a group of dwarves and plunged into the middle of a dwarven civil war. The three are now forced to try and escape a violent underground world ruled by Norse Gods, kings, and magic users. Will the three make it back to the surface unscathed?   Book 2   Book 3   Book 4