Spider, an adventurous 12 year old, takes his new friends, Ben and Kate, across the harbour to a deserted old mansion, Castle House. Two other boys disappear before their eyes in the overgrown grounds. The eccentric elderly owner suddenly returns, and Spider and his friends find a secret tunnel. Filmed around the natural bushland and bays of Sydney Harbour. it’s action all the way with enough crazy fun to keep children and their parents spellbound.