Sinister Summer Books in Order

Sinister Summer is Kiersten White's spooky, funny middle-grade mystery series about the Sinister-Winterbottom siblings. Theo is brave, impulsive, and eager to charge into danger. Her twin, Alexander, is cautious and anxious, which often means he notices the things everyone else would rather ignore. Their older sister, Wil, brings a different sort of perspective, even when she seems distracted by her phone.

At the start of Wretched Waterpark, the siblings' parents suddenly leave them in the care of their very strange Aunt Saffronia. She has little grasp of ordinary kid routines, glides more than she walks, and keeps sending the children to increasingly suspicious vacation spots with vague instructions to find what was lost.

Their first destination is Fathoms of Fun Waterpark, a gloomy place with ominous slides, disappearing people, and far too much mysterious goo. Theo and Alexander solve the immediate mystery, but the bigger question remains: where are their parents, and why does every stop seem connected to a larger puzzle?

Each book sends the siblings somewhere new. Vampiric Vacation visits a mountain spa that may have a vampire problem. Camp Creepy brings the family to a summer camp where everyone is unnervingly happy. Menacing Manor and Haunted Holiday continue the search through more gothic, oddball locations while bringing earlier clues and characters back into play.

The churros are never reliable.

The series is spooky without becoming relentlessly grim. It has monsters, elaborate settings, missing people, creepy grown-ups, and secrets, but it also has jokes, sibling banter, and a warm belief that being different is not the same as being broken. Alexander's worries are treated as part of who he is, not something he has to erase to become useful. Theo's boldness is helpful, but it can also get her into trouble.

Aunt Saffronia's bizarre vacation plan gives every installment a self-contained mystery, while the missing-parent story ties the five books together. Readers who enjoy strange mansions, amusement parks after dark, odd clues, and heroes who are kind even when they are frightened will find a lot to like here.

Start with Wretched Waterpark. The mysteries become more connected as the series goes on, and the final book, Haunted Holiday, brings the Sinister-Winterbottoms' long search toward its answer.