Cyril discovers that if he puts his mouth above the dinner table, he can scoop up some food, and the others follow suit. After dinner, they look outside and see the besieging army polishing their weapons and preparing a battering ram. The children arm themselves with daggers and gather stones to drop on the enemies’ heads. Anthea thinks to ask Martha to put some biscuits in her pocket, as her hands are dirty, and gains another source of invisible food.

Robert sticks his tongue out at Jakin, a soldier he met earlier, and when the others praise his bravery, Cyril grows jealous. A soldier demands their surrender, and Robert refuses. Jakin gets inside by swimming through the moat and entering through a window, and Robert locks him in a room while he secures the window. Jakin manages to lower the drawbridge, and soldiers pour into the castle as the children drop stones and pour water on their heads from above.

The sun sets, and suddenly everything returns to normal. The children agree that the adventure was exciting, and Anthea is just congratulating them all for not quarreling with each other or anyone else when Martha appears.