The Vexed Generation (Magic 2.0, Band 6)

Mattie and Brewster are normal, typical 16-year-old twins who live with their normal, boring parents: Martin and Gwen Banks. Normal and boring, that is, until the day their father's best friend shows up at their house—dressed in what appears to be a bathrobe. The next thing Mattie and Brewster know, their parents are frozen like human statues in their living room, the guy in the bathrobe has vanished, and they need to find answers—fast. The twins set off on a quest to discover the truth of their parents' lives. Along the way they find secrets, lies, magic, time travel, strange new friends, stranger new enemies, and a really weird dirigible (which, they're told repeatedly, is not a blimp). It is a twisted and bizarre trail that, they hope, will lead them to the man they blame for their parents' peril: Phillip.