In search of her brother, a girl named Carolyn finds herself in the underworld, whose gates open only once every 600 years on Halloween. 

SYNOPSIS:

Carolyn and her younger brother Liam are struggling to cope with

the loss of their mother. When she left them earlier than

expected, all responsibility for the home, school, finances, and

upbringing fell entirely on the older sister, who, despite her

burden of responsibilities, even on Halloween, a holiday that once

brought their whole family together, bringing them countless

moments of happiness, she was unable to find the time to go trick-or-treating with her

brother in costumes when he

needed it most. However, Halloween is not just a holiday with

candy and joy, it is also the key to the passage to the secret

underground world, where the ghosts of people who have died on earth

wander. Once every 600 years, on this day, under a full moon,

a mortal can enter this forbidden

place, as Liam did, running away from his own sister to

his mother's grave, where an entrance appeared, and from

which a familiar, fatherly voice beckoned the boy

voice. Carolyn notices her brother is missing and goes to look for him,

knowing that of all the places in the world, he would first

go to the cemetery, where she sees him jumping into

the pit. The girl quickly rushes after him, pushing him away from

a mysterious figure that looks like their mother, tearing out one

of the pages of the book that the creature is holding in its hands.After

that, the floor collapses beneath them, and they are scattered

across different parts of the underworld. In this afterlife, Carolyn

has to hide from other ghosts, who are a mass of

hatred and aggression, while getting to know another

spirit, Alan, who, unlike the other ghosts, looks like a

young man, about the same age as the girl. He

explains the rules of existence in this place, helps

her escape from evil spirits, and often guides her along shortcuts

to her goal. Together, they overcome obstacles, terrifying

creatures, and other adversities on their way, searching for Liam, who

is also somewhere here, in the abyss of nightmares and horror, from which

Carolyn must leave this world before dawn so as not to become

part of it.