Everything scares Miranda: spiders, germs, bullies and especially ghosts. But when the ghost turns out to be her own twin sister, Melody, Miranda is whirled into magical fun. At first she enjoys helping Melody with an earth homework assignment - until she discovers the homework means matchmaking her own mother to the father of Miranda's worse enemy, Heather Drew. Miranda loves having her sister around. But she does NOT want a bully for a stepsister. So Miranda comes up with a plan to stop her sister. Only does she stand a chance against a ghost who can float in the air, freeze time and zap objects?

As Miranda learns to adjust to her newly-blended family, her ghostly twin Melody leaves Ghostland and returns to earth to be with her.

Miranda and Melody try to keep Miranda's teacher, Miss Wynde from finding Steven, an unhappy ghost who lives in the backyard with his cat Velvet.

Heather, Melody and Miranda have their hands full babysitting half-brother Jeremy, a giant-sized dog named Harley, and a shy little ghost named Beth