heir is a play on words for "air", and breathing on the mirrors will reveal a message. Doubting himself, however, they allow their lead to slip away. Finally, Simon listens to Adrian about his theory, and they win the first task. Task two sees the teams head for the London Library, where waiting for them are individual cryptic clues. While Mairianne and Saskia swiftly figure out that the clue is in fact catalogue directories to find a specific book in a library of literally millions, Simon refuses to listen to Adrian, believing the clue is itself an encryption. While they struggle, Saskia takes the lead and finds the next clue, to head to a nearby park. She and Nat arrive and Saskia quickly spots a Tudor rose, underneath which is the clue, Old Royal Naval College. There, the teams find a digraphic substitution cipher, and using the six symbols they learnt from around the world, they crack the code as "THE PLACENTIA", the courtyard outside. While both Simon and Saskia look around the area (Simon actually walking past where they must go next), Suzie suggests she and Marianne try to find underground access. The idea pays off, with Mairianne finding the seventh symbol. After much time-wasting, Saskia also finds the symbol, thereby giving her another chance in the final stage. Not long later, Simon and Adrian arrive to find only the poison chalice. With just two teams remaining, The Search moves on to Edinburgh, Scotland. Here, Jamie tells the contestants that they'll find their next clue at Edinburgh Castle, Queen Mary's home while she was pregnant with James I. Both teams run up the Royal Mile to the castle, and are directed to Mary's private quarters (which they notice as a symbol outside corresponds with the seventh symbol). There, they find a piece of parchment and a cryptex. The parchment shows many Roman numerals, the answer being that they show the Tudor line of monarchs, the next in the sequence being James I or James VI in terms of Scotland, so the answer for the cryptex is SIXTH. Saskia works her mathematical brain looking for statistical logic in the sequence, naturally to little avail. Meanwhile, Mairianne remarkably comes to the correct answer in virtually moments of looking at the clue. Inside the cryptex is a clue to follow the hidden passageway. Pressing on the walls reveals a secret room, and