On the Underground Grove there are round rocks near water. Push them into the water so they end up forming stepping stones on a river on the upper part of the Grove, opening the way to face Parafrosini, the final succubus of the place. After that, you don't need help to proceed.I'm kinda confused. I played the ch 3 demo version and haven't played since. I forgot about the objective, can anyone tell me what to do?