The twins seem to take an instant dislike to the Five, who also meet two fellow paying guests: an American Mr Henning and his son, Junior.

Mr Henning and Junior prove themselves a nuisance to the household by rudely ordering around Mrs Philpot.

When Junior demands breakfast in bed, George teaches him a lesson, making him agree to be more pleasant.

Initially they are unsuccessful but the twins' dog Snippet and their jackdaw Nosey lead them to a burrow, beneath which the secret passage stretches out.

The adventure ends with Julian, Dick, Anne and George along with Timmy planning to stay at the farm to observe the excavation of the treasure.