

But now that he has been designated as a Solver, he is pulled into a new life where he must travel the world with other Solvers, attempting to solve the latest deadly riddles left by POG. Kaito suddenly finds himself caught up in a lethal Philosopher's Puzzle made by the sinister group POG, a murderous maze of trap upon trap, where failing to solve the secret correctly will result in death! Fortunately, Kaito's skills prove up to the first test, both for himself and his childhood friend Nanoha, who is also caught up in the deadly scheme. Kaito is so brilliant, in fact, that when he's asked to take some 'special' tests of his unique ability, he immediately suspects that the test itself is a test. Many associations try to find it and train people who can solve it.Kaito Daimon would be a completely average high school student except for one thing: he's a "demon" at solving puzzles. It is an unusual puzzle in that it takes two potential "Phi Brains" to solve it. The puzzle's location and physical form are currently unknown. The Puzzle of God ( 神のパズル Kami no Pazuru) is a legendary puzzle, that seals the "Book of God", said to unravel all the mysteries of the universe. It is noteworthy that many of these puzzles are not dangerous in nature, but the conditions for losing are against the wishes of Kaito and the gang. Similar to the Fool's Puzzles, the Puzzles of Judgement offer no sort of treasure to the winner.

The Puzzles of Judgement ( 裁きのパズル Sabaki no Pazuru) are made by the Orpheus Order members and people whose emotions were taken over by the fake Orpheus artifacts. Daimon Kaito notes that the Fool's Puzzles feel "cold", due to the fact they are built with the intention of nothing but forcing the development of the "Phi Brain". A Solver with no potential to achieve the "Phi Brain" would endanger his/her life.

Unlike the "Puzzle of the Wise", there is no "treasure" sealed. The Fool's Puzzles ( 愚者のパズル Gusha no Pazuru) are made with the goal to bring out an individual's "Phi Brain" potential and is of a high degree of difficulty. Although initially opposed to solving them, Daimon Kaito realises quickly that he enjoys the challenges set as well as admiring the feelings of the Giver, on multiple occasions noting that he can "feel the warmth" of the puzzle. Only those who have the potential to solve the puzzle will be able to acquire the "treasure". They are very difficult and almost impossible to solve. The stonehenge and the pyramids are examples in ancient times. The Sage's Puzzles ( 賢者のパズル Kenja no Pazuru) are created in order to seal a client's "treasure"( 財).
