You explain to the goblin that under the laws of the state of California -- which is where you are, have I forgotten to mention this anywhere else in the adventure? You're in California. Dang. I feel like this could have been useful to you earlier -- ...under the laws of the state of California rings must be returned to the giver, unless the giver broke off the engagement. The goblin, being a famously law-abiding sort, sees your point and agrees that you should return the ring. The situation is resolved amicably and with deference to the local laws here in California, where the story took place all along. As a thank you, the ghost and goblin both help you out of the cave and send you towards the tent, where you arrive in time to get a good morning's rest.