Wandering Galileo (迷えるガリレオ Mayoeru Garireo) is the fifth episode of Phi Brain: Kami no Puzzle Season Two and the thirtieth episode of the anime series overall.
Gammon's frustration concerning the Orpheus Order's attempt to target Miharu leads to a slump in the puzzles he makes under his pen name, Setsu Chidou. When he returns home that night, he finds Doubt waiting for him, offering him the chance to join the Orpheus Order. The next day, Gammon asks the POG for assistance and meets up with Elena, who becomes concerned about Gammon's desire to ditch puzzles in favor of revenge. The next day, without warning, Kaito challenges Gammon to solve the puzzles he made, based on the ones Gammon made the first time they met. As he solves them, Gammon's resolve returns and remembers his love for puzzles. Afterwards, Gammon sends a letter to Doubt rejecting his offer before vowing to make better puzzles than before, while Freecell prepares to make a move on Root Academy.