In The Mystery of the Singing Ghost, the Aldens fix up the house that their cousins are moving into. There’s just one problem--it seems to be haunted by a ghost who sings! A mysterious mansion alive with skeletons is the setting for The Mystery at Skeleton Point. And finally, in The Mystery of the Mummy’s Curse, the Aldens start to believe in the power of the 4,000-year-old sarcophagus on exhibit at Greenfield Museum. Boo!