A young timid boy stumbles upon a key that leads him into a series of adventures that both takes seven days and spans all of space and time. Arthur Penhaligon must travel through seven kingdoms to collect seven keys (giving him greater power) and seven parts to the will left by the Great Architect of All (greater knowledge). Arthur is pushed forwards, at various times through the series, by motives both high and low, from protecting his friends and family (and the world) to gaining power improve his own lot in life and claim his 'inheritance'.
This Young Adult series has a strong Judeo-Christian theme running through the series. God and the Satan are major characters and angels and demons abound. Along with the seven days of the week there are seven virtues and seven sins that are incorporated into the story line. For all that, the books are not preachy and mix fantastic realms as a backdrop for a set of great adventures. The only thing missing was ninjas.
1. Mister Monday
Arthur finds a key to a mysterious house. He learns that the Great Architect has disappeared and left her 'living' Will to seven Trustees. The trustees decide to ignore the Will and take control of the Kingdom (of which Earth is a minor sub-realm). Control is vested in seven keys. Arthur learns that he is apparently the Heir to the Architect and expected to wrest control of the keys from the trustees and execute the will. Mister Monday is first.2. Grim Tuesday
Arthur's family is in great danger and there's no going back, as much as Arthur wishes it would all go away. Arthur learns more about the House, the challenges he will face even if he can defeat Tuesday, and the ultimate peril that can end his race to collect all the keys.3. Drowned Wednesday
This time its pirates. Lady Wednesday is not so much the opponent that Monday and Tuesday were, as she is a dangerous force of nature that needs to be solved. As the mystery of the House unfolds before him Arthur realizes that he is involved in something more complicated than a treasure hunt.
Each story brings a new world, virtue acquired or understood, and a new "sin" to face. After pirates will it be Ninjas next?4. Sir Thursday
Arthur goes to war. He is separated from his friends and his own past as he is drafted into the Glorious Army of the Architect. His "real" world friend Leaf must destroy his evil doppelganger while he fights his way through basic training and the ever-growing threat from the chaos from outside.5. Lady Friday
Mirror mirror on the wall... Arthur is on his own again and his friends are in peril as chaos threatens to overwhelm the kingdom. The House is itself in peril and Saturday (and Sunday) are already actively opposing Arthur. Instead of direct confrontation Arthur's must deal with an offer from Lady Friday that is hard to refuse.6. Superior Saturday
Saturday is the top dog and Lord Sunday is not playing the game, giving Saturday his proxy. Arthur faces his greatest challenge as he comes to realize he cannot match Saturday's sorcerous power power, even with all the power of the first five key at his service. Even the Will can no longer be trusted. Will even the sixth Key be enough to defeat Saturday?7. Lord Sunday
The seven Keys come together and the Will is complete but not everything is as it seems. The Kingdom is never going to be the same again... or is it? Arthur will never be the same again... or will he? The epic adventure of Arthur Penhaligon is comes to an end.