When fearful twelve-year-old Charlie and his bolder younger sister are sent to visit a grandmother they never knew they had, they discover a dark secret.

A visit to Grandmother's house has never been so scary…

Twelve-year-old Charlie Ougght knows something is fishy when he and his little sister Georgie are sent away to spend time with a grandmother they've never met. Grandmother Pearl and her sister Grandmother Opal seem harmless enough, but Charlie soon uncovers a dastardly plot-the grandmothers are acting as minions for an ancient queen desperate to rule the world. Can Charlie and Georgie find a way to save themselves and the other children held captive in the Queen's lair before it's too late?