Julie Walters stars as a single mother seemingly haunted by a sinister telephone system that seems to have become an evil intelligence in its own right. Julie Walters stars as a single mother seemingly haunted by a sinister telephone system that seems to have become an evil intelligence in its own right. Julie Walters stars as a single mother seemingly haunted by a sinister telephone system that seems to have become an evil intelligence in its own right. Julie Walters stars as a single mother seemingly haunted by a sinister telephone system that seems to have become an evil intelligence in its own right.