Mister Monday

Two mysterious men suddenly appear right when Arthur Penhaligon, a 12-year-old boy, is having a severe asthma attack at school. The one, called Sneezer, convinces the other, called Monday, to give Arthur a 'Key', which looks like a clock hand. When they disappear again, there is a small book in their place, which Arthur takes.

He spends a week in the hospital. Once back at home, he uses the 'Key' to open the book, which is called The Compleat Atlas of the House and Immediate Environs and describes the House, which as far as he knows is just a building near where he lives. That night he is attacked by an evil dog-faced creature which fits the description of creatures a classmate saw during his asthma attack; the Key protects him by bringing his ceramic Komodo dragon to life.

The next day at school, he hears that the two classmates that helped him during his asthma attack have caught a mysterious disease. He has to deal with more dogfaces and is also attacked by a stronger creature, Monday's 'Noon'. The 'Noon' can only stay on Earth between noon and one o'clock, and Artur manages to evade him. Meanwhile, a quarantine team has arrived at the school because they believe the new mysterious disease originates there. Arthur gets a message to come to the House, and gets out of the school by releasing the Key, which had been helping him breathe. While being transported to the hospital, he escapes, and he goes to the House.

He discovers that the House is in fact a whole world of its own, and as he travels it he hears that it was created together with the universe by a divine being called the 'Architect', who has gone away, leaving a 'Will', and left control of the House to seven 'Trustees', of which Monday is one. He is told the Trustees are not following the 'Will', which they have split up into seven parts and hidden, and that he, Arthur, is the 'Rightful Heir' and must take back the House. For most of this journey he is accompanied by a cockney girl-child named Suzy Turquoise Blue and other so-called 'Piper's Children'.

Arthur defeats mister Monday, capturing Monday's part of the House, freeing the first part of the Will and gaining another clock hand, which combines with his clock hand to become the full Key. Then, the first part of the Will takes the form of a lady, named Dame Primus. One of Monday's former servants, who are now loyal to Arthur, gives him something that will cure the disease that the dogfaces brought to his town. He then leaves Dame Primus in control and returns to Earth, where the disease is cured. The book ends with Dame Primus contacting him using a phone for emergencies, right at midnight when the day has become Tuesday.

• Mister Monday title listing at the Internet Speculative Fiction Database