After their family relocates, Sam and Jim meet librarian Mizz Tiggle, the nefarious Ink Thief and other mysterious creatures.
When Jim is lured into the lair of The Ink Thief, Samantha turns to the Bumps in an attempt to save her brother.
Sam learns The Ink Thief's origins, Mizz Tiggle calls a meeting of the Official Organization of Bumps, and Jim discovers a page which provides his captor with immense superpowers.
Samantha and Mizz Tiggle travel through the Apopalyptic Spiral to reunite the Four Bumps of the Apopalypse. Meanwhile, Jim discovers The Ink Thief can increase his power by stealing the life force from other Bumps.
Dog tries to protect the library as Samantha, Mizz Tiggle and Snoop go to meet Rock. Meanwhile, The Ink Thief drains his powers faster than his minions can collect more.
Mizz Tiggle finds the other two Bumps of the Apopalypse. Also, Snoop stands up to The Ink Thief and his cronies in an effort to protect Dog.
The Ink Thief is defeated with aid from Big Balloonie.