There's a Dungeon in My Basement

After the death of a grandfather he never knew, Caleb Holdstock inherits a mysterious mansion. The place needs a lot of work if it's to be liveable, but the truly strange thing about it is what's in the basement. A doorway drawn in chalk. It seems harmless at first, until a midnight encounter with a silver-haired elf proves that this doorway is, in fact, the entrance to another world. With knowledge of a magical world beyond Earth, Caleb's life will never be the same again. And the best thing about it? He can travel back and forth freely.

After discovering the ability to improve items by opening portals into them, Caleb's life has changed completely. With an elf girlfriend from a fantasy world, as well as his own childhood sweetheart, things are looking up. When the reality of his elf girlfriend's debts become clear, Caleb offers to help pay them off. It'll mean crossing the threshold into the Wyrdworld and meeting with her vampiric creditors. To say Caleb is a little tentative would be putting it lightly.