The Adventures of the Cucumber. Volume 1. The Donut Kingdom

Know-it-all Cucumber has just entered the best school of magic and is very proud of himself. But there’s a problem: the Seven Kingdoms are in danger: the evil queen Cordelia has seized power and wants to summon the Knight of the Terrible Doom.
Cucumber, the valiant hero he doesn't want to be, will have to put his books aside and, together with his adventure-seeking sister Almond, embark on an exciting quest for the Lightning Sword - the only weapon that can defeat the Knight of the Terrible Doom.
Will this brother and sister be able to protect the world in its darkest hour?