Complex sentence: Annie, accompanied by Bill Creek, return to her mother's house where they discover a hidden room, one which Annie has absolutely no recollection of, and, when Bill and nobody else will take her seriously, recruits her psychic friend, Stevie.
Split into simpler sentences: Annie, accompanied by Bill Creek, return to her mother's house where they discover a hidden room, one which Annie has absolutely no recollection of. When nobody else will take her seriously, she recruits her psychic friend, Stevie.