In this tongue-in-cheek take on classic themes in children's literature, the four Willoughby children set about to become "deserving orphans" after their neglectful parents embark on a treacherous around-the-world adventure, leaving them in the care of an odious nanny.

First-grader Jake "The Pain" and his sister, third-grader Abigail "The Great One" have more adventures, including visiting their cousins in New York and celebrating their cat Fluzzy's birthday.

Xena and Xander Holmes, an American brother and sister living in London for a year, discover that Sherlock Holmes was their great-great-great grandfather when they are inducted into the Society for the Preservation of Famous Detectives and given his unsolved casebook, from which they attempt to solve the case of a famous missing painting.