The moment the Grace family moves into the dilapidated Spiderwick Estate, strange things begin to happen. Jared, a curious, adventurous boy, quickly seeks out and finds the hidden laboratory of his great great uncle Arthur Spiderwick. He unleashes a mysterious force when he locates a field guide full of the secrets of the magical creatures that inhabit the forest surrounding the mansion. His twin brother Simon is calm and reserved but is rapidly drawn...

In 1930s England, Tony and Brenda Last and their son, John Andrew, live an idyllic life in the huge Victorian country house that is the symbol of Tony's family pride. The chance arrival of a penniless scrounger irrevocably shatters the gentle balance of their lives as Brenda's search for excitement and Tony's determination to hold on to what is his eventually lead in the direction of divorce and send Tony to South America.