Episodes: 25Status: Completed
Alternate Titles: Phi Brain: Kami no Puzzle - Shukuteki! Rätsel-hen,Phi Brain: Puzzle of God 3,Phi Brain: Kami no Puzzle Dai 3, Phi Brain: Kami no Puzzle Third Season, Phi Brain: Kami no Puzzle 3rd Season, Phi Brain: Puzzle of God - Nemesis! Raetsel-hen,ファイ・ブレイン 〜神のパズル 宿敵！レイツェル編
"Are puzzles really necessary in this world?" In order to restore Jin's memory, Kaito and his friends go on a puzzle-viewing journey to England. As they're walking through the underground maze beneath the church, where young Kaito and Rook first met Jin, a mysterious girl appears in front of them. Jin calls the girl by the name "Raetsel". It seems they know each other. However, she suddenly disappears and takes Jin with her. What's more, the traps in the underground maze are activated and start coming after Kaito and his friends.