Name Of Film Please

[lazylocks01]

Film possibly from 80's and can't remember name.

Was about a boy and some if not all of the fool he is with his older brother and sister.
The sister gets captured and the brothers find she is being used in cult ritual where they can only watch from hiding place out of fear of being captured themselves,
The sister is wrapped up like mummy , carried out on stretcher I think and place in middle of floor where hot liquid run through maze like system while main baddy performs ritual, the girl dies and then there is a fire

Thanks in advance

[CrapAtCryptics]

I`m not quite sure you have the plot right but it sounds a bit like Young Sherlock Holmes

[CrapAtCryptics]

Is this the clip

https://www.youtube.com/watch?v=QzahXAGAL9I