Nine-year-old Dennis, whose uncle and father died within a year of one another, is visited by the ghost of his uncle, and together they settle some unfinished business.

Fifth-grader Mabel (code name Sunflower) wrote the Rules for a Successful Life as an Undercover Secret Agent, so when her parents leave town abruptly she is not too worried--but when her beloved Aunt Gertie is arrested, and her objectionable Uncle Frank and Aunt Stella (Frankenstella) and her annoying (but clever) cousin Victoria take over her house and the family's private museum, Mabel begins to smell a rat and she is determined to find out what...

Beastologist-in-training Nathaniel Fludd and his Aunt Phil nurse a mysteriously ill unicorn, try to stop Obediah from taking the unicorn's horn, and finally get a solid lead on the whereabouts of Nathaniel's parents.

Gavin wants to make a good impression at Carver Elementary, where no one knows he excels at soccer and skateboarding, but an annoying big sister, a bully, and his great aunt's Pomeranian are not helping.