If the party is found they will be escorted, (at sword point), to Darkstone to decide what needs to be done with them. Depending on answers from the party and the attitude of the party, there are several things that could happen.
1) Obviously, if Darkstone doesn't like their tone or answers he will ordered them killed. There are fifty adults and around ten children in the village. Around a quarter would prove to be a challenge to the party. (These people should be considered fighters of the same if not a few levels lower then the players.) They could fight their way out, but it would be bloody.
2) Darkstone takes their answers at face value and turns them around and sends them back to the surface, thinking they are not a threat. He will, however, require a payment for the freedom. The GM can come up with what that is.
3) Darkstone may really like their answers and ask them to do something for him in exchange for their freedom. This small task might be to go further into the tunnels and take out a batch of large spiders and their goblin keepers that keep attacking the village.