Un parque de diversiones siniestro

Meet the Sinister-Winterbottom siblings: brave Theo, his shy twin, Alexander, and his older sister, Wil. They have to spend the summer with her aunt Saffronia, who doesn't know how often children should eat nor is she able to use a smartphone, and whose feet never seem to touch the ground when she slides...uh... she walks. When Aunt Saffronia suggests spending a week at a water park, they don't hesitate to accept. But the park is even stranger than Aunt Saffronia: the water slides look like tongues of gray gargoyles; employees wear creepy black dresses and communicate sinister messages; There's an impossible figure at the top of the slide tower, people are disappearing, and a suspicious slimy substance is leaking into the wave pool. Something mysterious is happening and it's up to the twins to get to the bottom of it. And we're talking about the mystery, NOT the wave pool. Definitely NOT the wave pool. But can Theo and Alexander escape its depths?