Previously, Arthur Penhaligon always managed to take a break from his exploits in his familiar earthly world. But after he took possession of the Third Key, he was unable to return to his family. New adventures overtook the boy before he had time to leave the halls of the mysterious House... By an absurd accident, Arthur picked up a seemingly harmless coin - and immediately found himself recruited as a soldier of the invincible army of Sir Thursday! Well, unlike Mister Monday and Gloomy Tuesday, Drowned Wednesday did not wish Arthur anything bad... Maybe this time it will work out? Garth Nix’s books have long been appreciated by young fans of mysterious stories. However, adults also read them with pleasure. And it’s not surprising, because the fantasy worlds of Nyx are always unique, and the adventures that befall the heroes are always unexpected. Sir Thursday is the fourth book in the Keys to the Kingdom series.