The screenwriter of the Istanbul Guardians series is busy preparing for the new episode to be released. When his boss asks him to write an episode introducing the Gümüşçüler Çarşısı (Silversmiths' Bazaar), he goes to Veli Dede's shop to do some research. The young woman finds herself in the midst of a great mystery at the shop she went to for research. According to the stories, there is a hidden treasure beneath Istanbul, and the secret of this treasure is entrusted to the silversmiths. Veli Dede is the last guardian of this treasure. The treasure is not a valuable stone like gold, diamonds, or rubies, but a life-giving water that heals those who drink it and keeps them from aging. After learning this, Aslı embarks on a mysterious adventure.